[C++知识库]多重嵌套求硬币组成

zhuy?

本人化工专业刚学编程20天小白，最近慕课上跟着浙大翁凯学才c语言，多重嵌套有一题有点问题求大佬解答

题目：有1，2，5?角三种硬币，设计程序输入多少元就输出所有硬币组成可能?

?老师给的代码如下

#include <stdio.h>

int main()
{
	int x;
	int one, two, five;
	
	scanf("%d", &x);
	for ( one = 1; one < x*10; one++ ) {
		for ( two = 1; two < x*10/2; two++ ) {
			for ( five = 1; five < x*10/5; five++ ) {
				if ( one + two*2 + five*5 == x*10 ) {
					printf("可以用%d个1角加%d个2角加%d个5角得到%d元\n", 
						one, two, five, x);
					break;
				}
			}
		}
	}
	
	return 0;
}

比如输入2，就会是以下结果?

?

?然后我想改成两重循环的for语句来满足要求，

#include <stdio.h>

int main()
{
	int x;
	int one, two, five;
	
	scanf("%d", &x);
	for ( one = 1; one < x*10; one++ ) {
		for ( two = 1; two < x*10/2; two++ ) {
			//for ( five = 1; five < x*10/5; five++ ) {
			five=x*10-one-2*two ;
				if ( five%5==0) {
					printf("可以用%d个1角加%d个2角加%d个5角得到%d元\n", 
						one, two, five/5, x);
					break;
				}
			
		}
	}
	
	return 0;
}

也输入2?

?

?然后结果就是上面的，一角就只有一个值，5角还用了负值，请问错在哪里？