//先写个最大公约数的吧. 另一个自己想吧.
#include<stdio.h>

divisor (int a, int b)
{
int a, b, i;

printf("Input a and b: ");
scanf("%d %d", &a, &b);

while (i)
{
i = a % b;
if (i == 0) printf(" Max divisor is %d", b);
a = b;
b = i;
}
}

int main(void)
{
int a, b,;

divisor (a, b);

getch ();
return 0;
}

int a(inta,intb)
{int i;
if((i%a==0)&&(i%b==0))return(i);
}

最小公倍数调用最大公约数的函数

#include"stdio.h"

int Mulmax(int num1,int num2)
{
int r,d,n1,n2;
n1=num1;
n2=num2;
if(n1<n2)
{ d=n1;
n1=n2;
n2=d;
}
while(n2>0)
{ r = n1 % n2;
n1 = n2;
n2 = r;
}
return(n1);
}

int Mulmin(int num1,int num2)
{
return(num1/Mulmax(num1,num2)*num2);
}
main()
{
int num1,num2;
scanf("%d%d",&num1,&num2);
printf("%d\n",Mulmax(num1,num2));
printf("%d\n",Mulmin(num1,num2));
}