Start New Discussion within our **Software Development Community** # Very Simple Prime Number Finder v1.8

```
/* By Kelechi Nze
My first prime project*/
// Section 1 : Precompiled Headers
#include <windows.h> // Uses the Windows header includes alot of windows commands
#include <iostream> // Uses the standard Input and Output commands
#include <fstream> // File stream
#include <string> // Allows string variable
// Section 2 : Pre-Main Code
using namespace std; // Uses the namespace std
// Section 3 : Main Code
int main()
{
// Section 3.1 : Asking the user if they want to run the program
const string NEWLINE = "\n"; // Sets NEWLINE constant to "\n"
system("TITLE Kelechi Nze's Prime Number Finder v1.8"); // Sets the Title
cout << "Hello this is my prime number searcher\nversion 1.8 \n"; // Squirts the information to the screen
cout << "Would you like to start finding primes ? (Y \ N)\n"; // Squirts the information to the screen
string firstdes; // First Desision String Variable Declaration
cin >> firstdes; // User input into firstdes
if (firstdes == "N" || firstdes == "n") /* If firstdes is equal to a variation of "n" runs
the next set of instructions*/
{ // Begins instructions
return 0; // Ends program
} // Ends instructions
// Section 3.2 : The Prime Structure
struct primes //My Prime number structure
{
ifstream startnumb; //The starting number file
ofstream passnumb; //Passnumb: where primes are stored
int number, factor, divider; /*Number: The actulal prime number "finder"
factor: What's a factor
Divider: What to divide the prime.number with to find if there is a prime there*/
}prime; //Only one object in the structure ? Yes !
// Section 3.3 : The first few instructions before the Prime number loop
prime.passnumb.open("UserStorage.txt"); // Opens UserStorage.txt OR creates a new one
prime.startnumb.open("startnumber.ini");// Opens startnumber.ini
prime.startnumb >> prime.number; // Puts the information from startnumb.ini and places it in prime.number
prime.startnumb.close(); // Closes startnumber.ini to make it's resorces available again
prime.divider = 1; // Sets prime.divider to 1
prime.factor = 2; // Sets prime.factor to 2
// Section 3.4 : The prime loop
primeloop: //The everlasting loop to get primes
if (prime.factor > 2) // If prime.factor is bigger than 2 run the next set of instructions
{ // Begins instructions
prime.factor = 2; // Sets prime.factor to 2
prime.number ++; // Increses prime.number by 1
prime.divider = 1; // Sets prime.divider to 2
goto primeloop; // The program goes to the primeloop: lable
} // Ends instructions
prime.divider ++; // Increses prime.divider by 1
if ((prime.number % prime.divider) == 0) // If prime.number has remainder 0 when divided by prime.divider run the next set of instructions
{ // Begins instructions
prime.factor ++; // Increses prime.factor by 1
} // Ends instructions
if (prime.factor == 2 && prime.divider == (prime.number / 2)) // If prime.factor is equal to 2 and prime.divider is equal to prime.number divided by 2 run the next set of instructions
{ // Begins instructions
cout << prime.number << " is prime \n"; // Squirts the information to the screen
prime.passnumb << prime.number << " is prime\n"; // Squirts the information to the screen
} // Ends instructions
if (prime.divider == (prime.number / 2)) // If prime.divider is equal to prime.number divided by 2 run the next set of instructions
{ // Begins instructions
prime.factor = 2; // Sets prime.factor to 2
prime.number ++; // Increses prime.number by 1
prime.divider = 1; // Sets prime.divider to 1
} // Ends instructions
goto primeloop; // Goes to the primeloop: label
prime.passnumb.close(); // Closes prime.passnumb file
}
// Section 4 : Post-Main Code
```