判断正负数 – 分支结构

void main()
{
   int num;

   printf("Enter a number: \n");
   scanf("%d", &num);
   if (num > 0)
   printf("%d is a positive number \n", num);
   else if (num < 0)
   printf("%d is a negative number \n", num);
   else
   printf("0 is neither positive nor negative");
}

Enter a number:
-3
-3 is a negative number