题解 | 计算某字符出现次数

#include <stdio.h>
#include<string.h>

int count_num(char *s,char c){
    int count = 0;
    int i;
    for(i = 0;s[i] != '\0';i++){
        if(c >= 65 && c <= 90 ){
            if(s[i] == c || s[i] == c + 32){
                count ++;
            }
        }
         if( c >= 97 && c <= 122){
            if(s[i] == c || s[i] == c - 32){
                count ++;
            }
        }
        if(c >= 48 && c <= 57){
            if(s[i] == c){
                count ++;
            }
        }
    }
    return count;
}
int main() {
     char c[2000] = {0};
     char ch;

     fgets(c,2000,stdin);
     scanf("%c",&ch);

    printf("%d",count_num(c, ch)) ;
    return 0;
}