/* 
Program: prime-factoring-array.c (Report comments/bugs to chikh@yuntech.edu.tw)
Function: 
*/

#include <stdio.h>

int indx = 0;				
int factor[100];   

void divide(int n, int divisor) 
{
	if (divisor > n)
		return;
	else if (n%divisor != 0)
		divide(n,divisor+1);
	else {
		printf("%d ",factor[indx++] = divisor);
		divide(n/divisor,divisor);
	}
}

int main()
{
	int i, j, n; 
	
	printf("輸入欲因式分解的正整數 ==> ");
	scanf("%d",&n);
	printf("\n質因數為：");
	divide(n,2); 
	printf("\n\n%d = ",n);
	for (i = 0; i < indx;) {
		printf("%d",factor[i]);
		for (j = 1; i+j < indx; j++) 
			if (factor[i+j] != factor[i]) break;
		if (j > 1) printf("^%d",j);
		if ((i=i+j) < indx) printf("×");
	}
	
	return 0;
}