#include<stdio.h>
int main()
{   
    char c;
    int n = 0;
   
    while(scanf("%c",&c))
    {
                    if(c=='\n')
                               break;
                    if(64<c<90||96<c<123)
                    {
                                  n++;
                    }
    }
    printf("%d",n);


return 0;

if(64<c<90||96<c<123)

这是啥？  把数学的写法，写进代码里了

大佬怎么修改啊,改成('A'<c<'Z'||'a'<c<'z')吗

((64<c&&c<90)||(96<c&&c<123))

逻辑运算符。。。  在c语言里，能像你这样用吗