题解 | #计算某字母出现次数#

#include<iostream>
#include<string>
using namespace std;

int main(){
    string s;
    getline(cin, s); // 含空格的一行输入要用getline
    char c, d;
    cin >> c;
    if (islower(c)) {
        d = c - 'a' + 'A';
    } else{
        d = c - 'A' + 'a';
    }
    int ans = 0;
    for (int i = 0; i < s.size(); ++i) {
        if (s[i] == c || s[i] == d)
            ans++;
    }

    cout << ans << endl;
    return 0;
}