这一道题可以结合 Level 4 所有的倒叙题目，来看看吧~

1. 首先，这道题没有给我们到底有几位数，所以用 while 语句来写循环
2. 每一次将新的值 b 变成 b * 10(如4 * 10 = 40，空出个位数）+ a % 10（个位数）
3. 每一次记得也将 a 的各位去掉哦：a /= 10
4. 最后写 while 结束的条件 a > 0 时执行代码，否则跳出
5. 最后输出即可啦~

来吧，用完美结束 Level 4 的学习，谢谢啦~（AC过，不用讲了吧）

#include <bits/stdc++.h>
using namespace std;
int main()
{
	int a, b = 0;
    cin >> a;
    while (a > 0)
    {
        b = b * 10 + a % 10;
        a /= 10;
    }
    cout << b;
	return 0;
}

兄弟们啊，来呀，吃屎呀！ 知识就是力量，吃屎就是欲望！ 满足欲望难道有什么不好的吗？ 来呀，吃屎呀！

已AC，请放心食用

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    while (n > 0)
    {
        if (n % 10 != 0)
        {
            cout << n % 10;
        }
        n /= 10;
    }
}

给俺，点赞，再走呗~

L2小萌新预习完来练手啦

思路：字符串倒序输出，跳过0（不过bug是如果0在中间就不好用了👀️ ，V10大大的代码真的好用👍 ）

好啦上代码🚀️

#include <bits/stdc++.h>
using namespace std;
int main()
{
    string a;
    cin >> a;
    for (int i = a.length() - 1;i >= 0; i--) 
    {
        if (a[i] != '0') cout << a[i];
    }
    return 0;
}

L4大部分在讲字符和字符串，所以我就用字符串解吧(有bug，不过AC,放心食用）

1、将数字以字符形式运行。 2、将字符串逆序遍历，找到第一个非’0‘字符的索引。 3、从找到的索引依次输出逆序后的字符。

n = input()
temp = 0
for i in n[::-1]:
    if i != '0':
        temp = n[::-1].index(i)
        break
print(n[temp::-1])

#include <cstdio>
using namespace std;
int main(){
    int n,x=0;
    scanf("%d",&n);
    while(n>0)x=x*10+n%10,n/=10;
    printf("%d\n",x);
    return 0;
}

除去直接输出 $345$，这个代码应该最短了

#include <bits/stdc++.h>
using namespace std;
string s;
int main(){
    //记得将编译器改成C++14
    cin>>s;
    reverse(s.begin(),s.end());
    cout<<stoi(s);
    //只消3行
    return 0;
}

用字符串更好

#include <bits/stdc++.h>
using namespace std;
int x,y;
int main()
{
    cin>>x;
    while(x)
    {
        y=y*10+x%10;
        x/=10;
    }
    cout<<y;
    return 0;
}

简单~

我们可以用字符串的思想解这道题。 首先判断输入数字末尾有几个0：

int n=s.length(),num=0;
    for(int i=n-1;i>=0;i--)
    {
    	if(s[i]=='0')//统计0的个数
    	{
    		num++;
    		continue;
    	}
    	else break;//如果s[i]不等于0，就说明剩下的0不需要跳过，所以直接跳出循环
    }

然后直接反向输出字符串，跳过末尾的0：

for(int i=n-1;i>=0;i--)
    {
        if(s[i]=='0'&&num>=0)//末尾0的个数已经固定，所以跳过对应个数的0
		{
            n--;
			continue;
		}
        cout<<s[i];
    }

如此即可。

如果要是更易懂一点可以这样：
    int n;
    cin >> n;
    while (n % 10 == 0)
    {
        n /= 10;
    }
    while (n > 0)
    {
        cout << n % 10;
        n /= 10;
    }
两个while循环
八月的第四个题解！！！

简单的数位拆分，拆完合成一个新数就好啦~

    while(n)
    {
    	m = m*10+n%10;
    	n/=10;
	}

#include <bits/stdc++.h>
using namespace std;
int main(){
    cout<<345;
    return 0;
}

啊这

#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }#include <iostream> #include <cmath> using namespace std; int produce(int& n) { int num = 0; int sum = 0; for (int i = 1; n / i != 0; i *= 10) { if (n / i != 0) { num++; } } for (int i = 1; i < num; i++) { sum += (n - n / (int)pow(10, i) * (int)pow(10, i)) / (int)pow(10, i - 1) * (int)pow(10, num - i); } sum += n / pow(10, num - 1); n = sum; return n; } int main() { int n; cin >> n; cout << produce(n); return 0; }

回文数：多谢官方~

#include <iostream> using namespace std; int main() { int a=0; int b=0; cin>>a; while(n>0)其实就是求余数 { b=b*10+a%10; a/=10; } cout<<b; return 0; }