使用C语言如何输出逆序数

#include<stdio.h>
#include<math.h>
int main() {
    int a,b,c,num,ans;
    printf("Input num：");
    scanf("%d",&num);
    a=fabs(num/100);
    b=fabs((num/10)%10);
    c=fabs(num%10);
    ans=c*100+b*10+a;
    printf("a=%d,b=%d,c=%d,ans=%d\n",a,b,c,ans);
    return 0;
}

#include<stdio.h>
int main() {
    int a,b,c,num;
    printf("Input number：\n");
    scanf("%d",&num);
    while(num<0) {
        num=num*-1;
    }
    a=num%10;
    b=num%100/10;
    c=num/100;
    printf("reversal number is %d\n",a*100+b*10+c);
    return 0;
}

#include <stdio.h>
#include <stdlib.h>

void fun(int num)
{
	char x = 0,flag = 0;

	if (num < 0)
	{
		num = -num;
		printf("-");
	}
	while (num>10)
	{
		x = num % 10;
		num /= 10;
		if (x == 0 && (!flag))
			continue;
		else
			printf("%d", x);
		flag = x;		 //标志位,
	}
	printf("%d\n", num);
}

int main()
{
	int num;
	scanf("%d", &num);
	fun(num);
	system("pause");
}