素数问题 高手帮忙.
我做了个素数的问题,要求判断文档里的数是否为素数 并且把其顺序输出,如
2 结果为:1
3 2
4 0
6 0
13 6
我的做法是:

#include <iostream>
#include <vector>
#include <fstream>
#include <string>
using namespace std;
void main()
{
int b[2000],k=1,count,va;
vector <int> prime(10000,1);
for(int i=2;i <100;i++)
if(prime[i])
for(int j=i;j*i <10000;j++)
prime[i*j]=0;
for(int a=2;a <10000;a++)
if(prime[a])
b[k++]=a;
count=k;
ifstream in( "prime.txt ");
for(string s; getline(in,s);)
for(istringstream sin(s);sin> > va;)
if(prime[va])
for(k=1;k <count;k++)
if(b[k]==va)
cout < <k < <endl;
cout < < "0 " < <endl;
}
编译错误如下:
:\Documents and Settings\lhb\11.cpp(20) : error C2079: 'sin ' uses undefined class 'basic_istringstream <char,struct std::char_traits <char> ,class std::allocator <char> > '
C:\Documents and Settings\lhb\11.cpp(20) : error C2440: 'initializing ' : cannot convert from 'class std::basic_string <char,struct std::char_traits <char> ,class std::allocator <char> > ' to 'int '
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.

[解决办法]
#include <sstream> //缺少这个头文件了
[解决办法]
istringstream 需要包含上面的头文件才可用