题解 | #计算某字符出现次数#

#include <iostream>
#include <string>
using namespace std;
//不区分大小写
int main() {
    string str;
    char s;
    int count = 0;
    //cin不能判断空格，换成getline(cin,str)
    //cin>>str;
    getline(cin, str);
    cin >> s;
    for (int i = 0; i < str.size(); i++) {
        //由于不知道字符的大小写，用asci码+32和-32判断,相等是特殊情况
        if (str[i] >= 'A' && str[i] <= 'Z') {
            if (str[i] == s || str[i] + 32 == s)
                count++;
        } else if (str[i] >= 'a' || str[i] <= 'z') {
            if(str[i]==s||str[i]-32==s)
            count++;
        }

        //判断数字，不要掉了
        else if (str[i] == s)
            count++;
    }

    cout << count;
    return 0;
}