题解 | 计算某字符出现次数

#include <iostream>
using namespace std;
int main() {
    string a;
    getline(cin,a);
    char b,f;
    cin>>b;
    int e = 0;//检测是不是字母，0为数字
    if(b>='a'&&b<='z'){
        f = char(int(b)-32);
        e = 1;
    }
    if(b>='A'&&b<='Z'){
        f = char(int(b)+32);
        e = 1;
    }
    int c = a.length()-1;
    int d = 0;
    for(int i = 0; i <= c ; i++){
        if(a[i] == b){
            d = d + 1;
        }
        if(e == 1){
            if(a[i] == f){
                d = d + 1;
            }
        }
    }
    cout<<d;
}