求任意一個正整數的逆序

# include<stdio.h>

int main()
{
    int x;
    scanf("%d",&x);
    
    int digit;
    
    while(x>0){
        
        digit = x%10;
        printf("%d",digit);
        x/=10;
    
    }
    return 0;
    
}

 

升級版：

# include<stdio.h>

int main()
{
    int x;
    scanf("%d",&x);
    
    int digit;
    int ret = 0;
    
    while(x>0){
        
        digit = x%10;
        ret =ret*10+digit;
        printf("x=%d,digit=%d,ret=%d\n",x,digit,ret);
        x/=10;
    }
    
    printf("ret=%d\n",ret);
    return 0;
    
}

空格輸出：

# include<stdio.h>

int main()
{
   int x;
   scanf("%d",&x);
   
   do {
       int d = x % 10;
       printf("%d",d);
       if(x > 9){
           printf(" ");
       }
       x /= 10;
   } while (x>0);
   
   printf("\n");
   
   return 0;
}