实验1.

#include <stdio.h> 
int main() {
    int x;
    printf("输入一个整数；\n") ;
    scanf("%d",&x);
    if(x%2==1)
       printf("是奇数");
    else 
       printf("是偶数");
    return 0;
}

#include <stdio.h>
int main(){
    int days;
    printf("输入一个整数:\n");
    scanf("%d",&days);
    if(days<=5&&days>=1)
       printf("workdays,fighting\n");
    else if(days==6||7)
       printf("weekend,relax~\n");
    else
       printf("Ooops,not in 1~7\n");
    return 0;
}

#include <stdio.h> 
int main(){
    printf("Hello,Mars!");
    return 0;
}

#include <stdio.h>
int product(int,int);
int main(void)
{
    int x,y,s;
    scanf("%d %d",&x,&y);
    s = product(x,y);
    printf("The mul is:%d",s);
    return 0;
}
int product(int a,int b)
{
    int mul;
    mul=a*b;
    return mul;
}