题解 | #计算某字符出现次数#

分清大小写和数字

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

int main() {
    string s;
    getline(cin, s);

    char check = getchar();
    
    int len  = size(s);
    int count = 0;
    // 小写：2，大写：1 数字 0
    int flag = (check>='a'&&check<='z')?2:(check>='A'&&check<='Z')?1:0;
    if(flag == 2){
        char upperCase = check-32;
        for(int i = 0; i < len; i ++){
            if(s[i]==check || s[i]==upperCase)
                count++;
        }
    }else if(flag == 1){
        char lowerCase = check + 32;
        for(int i = 0; i < len; i ++){
            if(s[i] == check || s[i] == lowerCase)
                count++;
        }
    }else{
        for(int i = 0; i < len; i ++)
            if(s[i] == check)
                count++;
    }
    
    cout << count << endl;
}
// 64 位输出请用 printf("%lld")