A+B十六进制

#include <cstdio>
#include <cstdlib>
#include <cmath>


using namespace std;


int main()
{
    long long A;long long B;
    while(scanf("%I64d%I64d",&A,&B)!=EOF)
    {
         long long C = A+B;
         if(C < 0)
            printf("-%I64X\n",-C);
         printf("%I64X\n",C);


    }
    return 0;

}

循环输出一个数字，怀疑是%I64d 位数不够，

#include <cstdio>#include <cstdlib>#include <cmath>using namespace std;int main(){    long long A;long long B;    while(scanf("%I64X%I64X",&A,&B)!=EOF)    {         long long C = A+B;         if(C < 0)            printf("-%I64X\n",-C);         printf("%I64X\n",C);    }    return 0;}

运行正常，但是会wa

#include<stdio.h>int main(){    long long  a,b;    while(scanf("%I64X%I64X",&a,&b)!=EOF)        printf(a+b >= 0?"%I64X\n":"-%I64X\n",a+b>0?a+b:-a-b);      return 0;}

ac的代码