#include<stdio.h>
   int main(){
       int a = 1 , sum = 0;
       while ( a <= 100 ){
          if ( a % 2 == 0 )
             sum = sum + a;
          a = a + 1;
       }
       printf ( "偶数之和为%d" , sum );
       return 0 ;
   }
这个代码有错吗?错在哪?

怎么我运行总是提示有一个错误呢?????????