#include<stdio.h>
int mysum(int a)
{
    int sum=0;
    if(a%2)
    sum=sum+a;
    return sum;
} 
int main()
{
    int a,b,c,i;
    printf("请输入数字的总数:");
    scanf("%d",&a);
    printf("请分别输入这些数\n");
    for(i=0;i<a;i++)
    {
        scanf("%d",&b);
    } 
    printf("这些整数中的和为%d\n",mysum(b));
    return 0;
}

#include<stdio.h>
double mypow(double x,int n)
{
    double c=1;
    int i;
    for(i=1;i<=n;i++)
    c=c*x;
    return c;
}
int main()
{
    double x;
    int n;
    printf("请输入x和n的值:");
    scanf("%lf %d",&x,&n);
    printf("结果为%.3f\n",mypow(x,n));
    return 0; 
}

#include<stdio.h>
double result;
void cylinder(double r,double height)
{
    result=3.14*r*r*height;
}
int main(void)
{ 
    double r,height;
    printf("请输入圆柱体的半径和高度:");
    scanf("%lf %lf",&r,&height);
    cylinder(r,height);
    printf("%.3f\n",result);
    return 0;
}