求指定范围内的所有素数

/*
Name: 求指定范围内的所有素数
Copyright: tonyee
Author: tonyee
Date: 20-03-09 18:50
Description: C++ 练习题
*/
#include <iostream>

using namespace std;

class PRIMENUM
{
int data[25];
int span1, span2;
int num;
public:
PRIMENUM(int n1,int n2)
{
num = 0;
span1 = n1, span2 = n2;
}
int isprime(int x);
void process()
{
for(int i = span1; i<=span2; i++)
{
if(isprime(i))
data[num++]=i;
}
}
void print()
{
cout << "num =" << num << endl;
int k = 0;
for(int i=0; i<num; i++)
{
cout << data[i] << '/t';
k++;
if(k%5==0)
cout << endl;
}
cout << endl;
}
};

int PRIMENUM::isprime(int x)
{
for(int i=2; i<x/2; i++)
if(x%i == 0)
return 0;
return 1;
}
int main()
{
PRIMENUM test(100,200);
test.process();
test.print();

system("PAUSE");
return EXIT_SUCCESS;
}