Question

c++程序:输出小于某个整数的求和，数据范围2<=n<=10000

Answer 1

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
int i,j,k,f,z;

scanf("%d",&i);
if(i<10000)
{
if(i/1000!=0)
{
printf("4\n");
}
else if(i/100!=0)
{
printf("3\n");
}
else if(i/10!=0)
{
printf("2\n");
}
else
{
printf("1\n");
}
}
else
{
printf("你输入的数据有误\n");
}
}

Answer 2

用if语句实现:if (n>= 2 &&n<=10000)

Answer 3

#include<stdio.h>
int main()
{int i,n,s=0;
scanf("%d",&n);
s=(1+n)*n/2;
printf("%d\n",s);
return 0;
}