#include<stdio.h>
int oddsum(int n)
{

    int sum;
    int i;
    for ( i=0;i<=n;i++)
       {
       sum=sum+i;
       
       }
    return sum;
}
    int main()  
{
    int sum;
    int n;
    printf("请输入n个数："); 
    scanf("%d",&n);    
    printf("%d",oddsum(n));
    return 0;
}

#include<stdio.h>
int double cylinder(double r,double height)
{
    double v;
    v=3.14*r^2*height;
    return 0; 
}
int main()
{ 
    double r,height,v;
    printf("请输入r的值：");
    scanf("%lf",r) ;
    printf("请输入height的值：");
    scanf("%lf",height);
    printf("圆柱体积为：","%lf=3.14*r^2",&v);
    return 0;
}

#include <stdio.h>
double mypow()
{
    double x,y=1;
    int n,i;
    printf("请输入底数和指数：");
    scanf("%lf %d",&x,&n); 
      y=y*x;
    printf("%f",y);
}
int main()
{
    mypow();
    return 0;
}