1原来char c;(c=getchar())!='\n可以用来输入一串字符。

#include <stdio.h>
int main(void) {
   
    char c;
    int letters = 0,space = 0,digit = 0,others = 0;
    printf("please input some characters\n");
    while((c = getchar())!='\n'){
   
        if(c>='a'&&c<='z'||c>='A'&&c<='Z'){
   
            letters++;
        }
        else if(c==' '){
   
            space++;
        }
        else if(c<='9'&&c>='0'){
   
            digit++;
        }
        else{
   
            others++;
        }
    }
    printf