为什么全错？求问

#include<stdio.h>
 
using namespace std;

   int main(){
  
   int a=0;
    
   scanf("%d\n",&a);
    
 if(a==1)
    
   printf("Today,I ate %d apple.\n",a);
      
  else if(a>1)
    
   printf("Today,I ate %d apples.\n",a);
      
  else if(a==0)
    
   printf("Today,I ate %d apple.\n",a);
      
  return 0;
 
  }