#include "stdio.h"
#include "string.h"
void main()
{
    int hao,a,b,c,d,max;
    char name[10];
   
    printf("候选人如下：\n");
    printf("1、张三\n2、李四\n3、王五\n4、赵六\n");
   
   a=b=c=d=0;
   hao = -1;
   
   for(;hao != 0;)
   {
           printf("请输入候选人的代号，按0结束：");
           scanf("%d",&hao);
           
           switch(hao)
           {
               case 1: a++;break;
               case 2: b++;break;
               case 3: c++;break;
               case 4: d++;break;
               case 0: break;
               default : printf("此票无效！\n");
           }
   }
   printf("投票结果如下：\n");
   printf("张三：%d票\n",a);
   printf("李四：%d票\n",b);
   printf("王五：%d票\n",c);
   printf("赵六：%d票\n",d);
   if(a>b)
           max = a; strcpy(name,"张三");
   else
           max = b; strcpy(name,"李四");
   if(c>max)
           max = c; strcpy(name,"王五");
   if(d>max)
           max = d; strcpy(name,"赵六");
   
   printf("恭喜%s被当选为班长\n",name);
      
   
   
   
}

是不是加点 {} 就行了，自己逻辑一下～～

#include "stdio.h"
#include "string.h"
void main()
{
    int hao,a,b,c,d,max;
    char name[10];
   
    printf("候选人如下：\n");
    printf("1、张三\n2、李四\n3、王五\n4、赵六\n");
   
   a=b=c=d=0;
   hao = -1;
   
   while (hao != 0)
   {
           printf("请输入候选人的代号，按0结束：");
           scanf("%d",&hao);
           
           switch(hao)
           {
               case 1: a++;break;
               case 2: b++;break;
               case 3: c++;break;
               case 4: d++;break;
               case 0: break;
               default : printf("此票无效！\n");
           }
   }
   printf("投票结果如下：\n");
   printf("张三：%d票\n",a);
   printf("李四：%d票\n",b);
   printf("王五：%d票\n",c);
   printf("赵六：%d票\n",d);
   if(a>b)
   {
           max = a; strcpy(name,"张三");
   }
   else
   {
           max = b; strcpy(name,"李四");
   }
   if(c>max)
   {
           max = c; strcpy(name,"王五");
   }
   else
   {
       if(d>max)
       {
            max = d;strcpy(name,"赵六");
       }
   }
   
   printf("恭喜%s被当选为班长\n",name);
      
   
   
   
}

第一次看见你这么用for的  for  while 要弄清楚哦

if只能执行下一条语句...

貌似你的break只能跳出switch而不能跳出for循环吧。。。else后面也需要加上花括号。。。

看错。。。