不特判z

#include<bits/stdc++.h>
using namespace std;
int sa[27];
int main()
{
	string g;
	getline(cin,g);
	for(int i=0;i<=g.length()-1;i++)
	{
		if(g[i]>='a'&&g[i]<='z')
		{
			g[i]=(g[i]+1)%'a'%26+'a';
		}
		if(g[i]>='A'&&g[i]<='Z')
		{
			g[i]=(g[i]+1)%'A'%26+'A';
		}
		cout<<g[i];
	}
	cout<<ansg;
	return 0;
}

改变了字符串的方法

#include <bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    getline(cin, s);
    for (int i = 0; i < s.length(); i++)
    {
        // 如果是小写或大写字母就进行加密
        if (('a' <= s[i] && s[i] <= 'z') ||
            ('A' <= s[i] && s[i] <= 'Z'))
        {
            if (s[i] == 'z')
                s[i] = 'a';
            else if (s[i] == 'Z')
                s[i] = 'A';
            else
                s[i] = s[i] + 1;
        }
    }
    cout << s << "\n";
    return 0;
}

加密完一个字符后就输出一个字符

#include <bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    getline(cin, s);
    for (int i = 0; i < s.length(); i++)
    {
        // 如果是小写或大写字母就进行加密
        if (('a' <= s[i] && s[i] <= 'z') ||
            ('A' <= s[i] && s[i] <= 'Z'))
        {
            if (s[i] == 'z')
                s[i] = 'a';
            else if (s[i] == 'Z')
                s[i] = 'A';
            else
                s[i] = s[i] + 1;
        }
        cout << s[i];
    }
    return 0;
}