int i, a, b, c, d;
        char e;
        printf("请输入一串字符\n");
        while ( ( e = getchar() ) != '\n' ) {
            if (e >= 'a' && e <= 'z' || e >= 'A' && e <= 'Z') {
                a++;
            } else if (e == ' ') {
                b++;
            } else if ( e >= '0' && e <= '9') {
                c++;
            } else {
                d++;
            }
            
        }
        printf("%d,%d,%d,%d", a,b,c,d);            //d的值有问题
问：d的值为啥不正常？

你没有赋初值吧都

问题是：你想要用d 来计算什么符号的数量？？？

#include<stdio.h>
int main()
{
   int i, a, b, c, d=0;
        char e;
        printf("请输入一串字符\n");
        while ( ( e = getchar() ) != '\n' ) {
            if (e >= 'a' && e <= 'z' || e >= 'A' && e <= 'Z')
                            a++;
             else
                 if (e == ' ')
                            b++;
                    else 
                       if ( e >= '0' && e <= '9')
                                    c++;
                             else
                                      d++;
       }
        printf("字母：%d,空格：%d,数字：%d,%d", a,b,c,d);     

 }

是的

谢谢大佬我果然还是新手

int i, a, b, c, d;
        for (i = 0; i < 3; i++) {
            a++;
            b++;
            c++;
            d++;
        }
        printf("%d\t,%d\t,%d\t,%d\t", a,b,c,d);
4       ,3      ,1708931        ,3
--------------------------------
Process exited after 0.361 seconds with return value 17
请按任意键继续. . .
这个为什么啊？

变量在使用之前要初始化，否则其值是随机的。不是你想象中的0

如果你没有赋初值的话  它就会这样
-858993457      ,-858993457     ,-858993457     ,-858993457     Press any key to continue

一般这种计数的 你都要先赋初值
#include<stdio.h>

int main(){
int i, a, b, c, d;
        a=0; b=0; c=0; d=0;//比如把它们都赋值0
        for (i = 0; i < 3; i++) {
            a++;
            b++;
            c++;
            d++;
        }
        printf("%d\t,%d\t,%d\t,%d\t", a,b,c,d);
  return 0;
}
3       ,3      ,3      ,3      Press any key to continue

这样结果才会对