topical media & game development

#### basic-program-code-04-Ex4-09.c

? / basic-program-code-04-Ex4-09.c

```
// EX4_09.CPP
// Calculating primes
include <iostream>
include <iomanip>
using std::cout;
using std::endl;
using std::setw;

int main()
{
const int MAX = 100;           // Number of primes required
long primes[MAX] = { 2,3,5 };  // First three primes defined
long trial = 5;                // Candidate prime
int count = 3;                 // Count of primes found
int found = 0;                 // Indicates when a prime is found

do
{
trial += 2;                      // Next value for checking
found = 0;                       // Set found indicator
for(int i = 0; i < count; i++)   // Try division by existing primes
{
found = (trial % *(primes + i)) == 0;// True for exact division
if(found)                          // If division is exact
break;                          // it's not a prime
}
if (found == 0)                  // We got one...
*(primes + count++) = trial;  // ...so save it in primes array
}while(count < MAX);

// Output primes 5 to a line
for(int i = 0; i < MAX; i++)
{
if(i % 5 == 0)                 // New line on 1st, and every 5th line
cout << endl;
cout << setw(10) << *(primes + i);
}
cout << endl;
return 0;
}
```

(C) Æliens 20/2/2008

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