c语言输出入门求解答

Question

想知道这个Presentation Error是哪里的问题啊

#include<stdio.h>
int main()
{
    int a,b;
    while(scanf("%d%d",&a,&b))
    {
        if(a==0 && b==0)
            break;
        printf("%d\n",a+b);
        printf("\n");
    }
    return 0;
}

Answer 1

while(scanf("%d%d",&a,&b))
->
while(scanf("%d%d",&a,&b) == 2)