#include <iostream>
using namespace std;
int main()
{
    int n, i, j;
    cin >> n;
    for (i = 1; i <= n; i += 1) //外层循环控制输出的行数
    {
        for (j = 0; j < n - i; j += 1) //输出字母前的空格
        {
            cout << " ";
        }
        for (j = i - 1; j; j -= 1) //输出字母塔左边部分字母
        { 
            cout << (char)('A' + j);
        }
        for (j = 0; j < i; j += 1) //输出字母塔右边部分字母
        {
            cout << (char)('A' + j);
        }
        cout << endl;
    }
    return 0;
}//代码已AC

这一道题可以分为左右两部分来做

已AC，请放心食用

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    char x = 'A', s = 'A';
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n - i; j++)
        {
            cout << " ";
        }
        for (int j = 1; j <= i - 1; j++)
        {
            cout << x;
            x--;
        }
        for (int j = 1; j <= i; j++)
        {
            cout << char(j + 'A' - 1);
        }
        s++;
        x = s;
        cout << endl;
    }
    return 0;
}

再把前两题的代码改一下

#include <bits/stdc++.h>
using namespace std;
int n;
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n-i;j++)
            cout<<" ";
        for(int j=1;j<=i*2-1;j++)
            cout<<char('A'+abs(i-j));
        cout<<endl;
    }
    return 0;
}