程序代码：

#include <stdio.h>
int max(int a,int b)
{    int c,m,n;
    if (a > 0 && b >0)
{
    m=a;
    n=b;
    c=m%n;
while (c != 0)
{
    m = n;
    n = c;
    c = m%n;
}
}    return n;
}
int min(int a,int b)
{    return a*b/max(a,b);
}
main()
{    int a,b;
    scanf("%d%d\n",&a,&b);
    printf("最大公约数：%d\n",max(a,b));
    printf("最小公倍数：%d",min(a,b));
}

程序代码：

#include <stdio.h>
int sum(int a,int b)
{    int sum;
    return sum=a+b;
}
int jian(int a,int b)
{    int jian;
    return jian=a-b;
}
int cheng(int a,int b)
{    int cheng;
    return cheng=a*b;
}
double chu(double a,double b)
{    double chu;
    return chu=a/b;
}
int yu(int a,int b)
{    int yu;
    return yu=a%b;
}
main()
{int a,b;
    scanf("%d%d\n",&a,&b);
    printf("相加：%d\n",sum(a,b));
    printf("相减：%d\n",jian(a,b));
    printf("相乘：%d\n",cheng(a,b));
    printf("相除：%lf\n",chu(a,b));
    printf("求余：%d\n",yu(a,b));
}