// prime number series
#include <iostream.h>
enumflag {green, red);
void main ()
{
long n, i, range;
flag myflag;
cout << "Enter a range:";
cin >> range;
for (i=1;n <= range; n++)
{
myflag = green;
for (i=2; l <= n/2; i++)
if(n%i == 0)
{
myflag = red;
break
}
if (myflag == green)
cout << n << endl;
}
}
Output of the above program:
Enter a range: 5
1
2
3
5
7