10_1.cpp

湖南大学ACM-OJ的部分题目代码

//求范围2~N中的质数，N在程序运行时由键盘输入

#include<iostream>
#include<iomanip>
#include<vector>
using namespace std;
void main(void)
{
	vector<int> A(10);
	int n;
	int primecount=0,i,j;
	cout<<"Enter a value >=2 as upper limit for prime numbers:";
	cin>>n;
	A[primecount++]=2;
	for(i=3;i<n;i++)
	{
		if(primecount==A.size())
			A.resize(primecount+10);
		if(i%2==0)
			continue;
		j=3;
		while(j<=i/2&&i%j!=0)
			j+=2;
		if(j>i/2)
			A[primecount++]=i;
	}
	for(i=0;i<primecount;i++)
	{
		cout<<setw(5)<<A[i];
		if((i+1)%10==0)
			cout<<endl;
	}
	cout<<endl;
}