用C++求1到N的和， - 编程论坛

#2

yyblackyy2010-04-20 00:38

Sn=(1+N)*N/2

输入N 输出Sn

#3

guoxijun2010-04-20 01:20

int n;
    long Sum=0;
    cout<<"Please input N :";
    cin>>n;
    for (int i=1;i<=n;++i)
    {
        Sum += i;
    }

#4

雨中楼2010-04-20 10:45

以下是引用yyblackyy在2010-4-20 00:38:04的发言：

Sn=(1+N)*N/2

输入N 输出Sn

(上底+下底)*高/2,呵呵这个好!

#5

qq3538079732010-04-20 10:54

#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
int x,j,sum=0;
cout<<"please enter a number: ";
cin>>x;
cout<<x;
cout<<"\n";
for(j=0;j<=x;j++)
sum+=j;
cout<<sum;
cout<<"\n";
return 0;
}

#6

yjj6340419262010-04-20 12:58

我晕谢伟你可真够恨的

#7

自欺欺人2010-04-20 18:08

都被说了6

#8

shiyuehai2010-04-20 20:51

应该很容易吧这个

#9

温度2010-04-23 23:20

#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
int x=1,j,sum=0;
cout<<"请输入一个数: ";
cin>>x;
cout<<x;
cout<<"\n";
for(j=0;j<=x;j++)
sum+=j;
cout<<sum;
cout<<"\n";
return 0;
}

#10

zhug2010-04-25 21:36

#include <iostream>
using namespace std;

int main()
{
int temp = -1;//默认设为-1
int sum = 0;//和
cout << "请输入一个数: ";
cin >> temp;
for(int i = 0; i < temp; i++)
sum = sum + i + 1; //累加
cout << sum << endl; //输出结果
return 0;
}

#11

aiyinsitan2010-04-25 22:23

#include"iostream.h"
main()
{
int sum,i;
sum=0;
cout"please input n:";
cin>>n;
for(i=1;i<=n;i++)
sum=sum+i;
cout<<"sum="<<endl;
}

#12

libaoan0012010-04-26 20:56

呵呵你应该改名叫伟谢

#13

神左手2010-04-26 22:00

以上几个都是很好的！

#14

baibing4852010-04-26 22:31

如果不怕数据溢出可以这么写，但是如果数据位数多了就不行了建议用数组

#15

2010-04-27 07:30

#include <iostream>
using namespace std;
int main()
{
    int a=-1;
    int n=0;
    cout<<"输入一个数";
    cin>>a;
    for(int c=0,c<a; i++)
        n=n+i+1 ；
    cout<<n
    return 0;
}

10楼的特别好懂    受教啦~

#16

aceryjs2010-04-30 19:51

#include"iostream.h"
int main()
{
int i,n,sum;
for(i=1;i<=n;i++)
{sum+=i;}
cout<<"sum="<<sum<<endl;
return 0;
}

#17

godfery2010-05-05 21:06

就是很简单的相信楼主肯定是初学吧！？

#18

谢伟2010-10-19 20:00

谢谢啦！！

#19

zhanghee2010-10-30 21:18

s = (a+b)*b/2

#20

爱上对方法国2010-10-30 21:32

#include<iostream>
using namespace std;
int main()
{
   int n;int sum(0);
   cout<<"please enter a number of your want"<<endl;
   cin>>n;
   for(int i=0;i<n;i++)
{sum=sum+i;
}
cout<<endl;
return 0;
}