C language: recursively implementing factorial of n

#include <stdio.h>
long f(int x);
int main()
{
    
	int a;
	printf(" Please enter the number of factorials to be calculated ：");
	scanf("%d",&a);
	printf("%d The factorial of is ：%d\n",a,f(a));
	return 0;
} 
long f(int x)
{
    
	long g;
	if(x<0){
    
		printf("x<0, Incorrect input ！");
	} 
	else if(x==1 || x==0){
    
		g = 1;
	}else{
    
		g = x*f(x-1);
	}
	return g;
}