求最小公倍数的三种方法

1.常规法

#include<stdio.h>
#include<stdlib.h>
int main(){
	int a, b, i,j;
	printf("请输入两个数\n");
	scanf("%d%d", &a, &b);
	for (i = 2;i<=a;i++){
		if (a%i == 0 && b%i == 0)
		{
			j = i;
		}
	}
	printf("最大公约数为：%d", j);
	system("pause");
return 0;
}

2.辗转相除法

#include<stdio.h>
#include<stdlib.h>
int main() {
	int a, b, c;
	printf("请输入两个数\n");
	scanf("%d%d", &a, &b);
	while (b!=0) {    //不用比较被除数和除数的大小
		c = a % b;
		a = b;
		b = c;
	}
	printf("最大公约数为：%d", a);
	system("pause");
	return 0;
}

3.更相减损法

#include<stdio.h>
int main() {
    int i = 0, j = 0, k = 0, a = 0, b = 0;
	scanf("%d%d", &i, &j);
	for (a = i,b = j;(a % 2 == 0) & (b % 2 == 0);) {
		a = a / 2;
		b = b / 2;
	}
	for (k=0;a!=b;) {
		while (a > b) {
			k = a - b;
			a = b;
			b = k;
		}
		if (a == b)
			break;
		k = b - a;
		a = a;
		b = k;
		}
	printf("%d与%d最大公约数为：%d\n",i,j,k);
	system("pause");
	return 0;
}