Visual C++ - Generating Prime Numbers

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I have given here the source code in Visual C++ for generating the prime numbers. The logic for prime number is quite simple.

 

Take any number, say N and iterate the loop through N/2 from 2. If any one of the number is divisble with 0 remainder, then it is not a prime number and then exit from the loop.

 

The variable bPrime is used to store and return whether the given number is a prime number or not.

Source Code

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#include <iostream>

#include <string>

 

 

bool IsPrimeNumber(int num)

{

    bool bPrime = true;

    int factor = num / 2;

    for(int i = 2; i <= factor; i++)

    {

        if( (num % i) == 0)

            bPrime = false;

    }

 

    return bPrime;

}

 

void GeneratePrimeNumbers(int max)

{

    std::cout << "All the prime numbers under " << max << " are given below:\n";

    int dispctr = 0;

    for(int i = 2; i <= max; i++)

    {

        if(IsPrimeNumber(i) == true)

        {

            std::cout << i << "\t";

            if(++dispctr >= 6)

            {

                std::cout << "\n";

                dispctr = 0;

            }

        }

    }

    std::cout << "\n";

}

 

int main()

{

    GeneratePrimeNumbers(1000);

    return 0;

} 

 

Output

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All the prime numbers under 1000 are given below:
2   3   5   7   11  13 
17  19  23  29  31  37 
41  43  47  53  59  61 
67  71  73  79  83  89 
97  101 103 107 109 113 
127 131 137 139 149 151 
157 163 167 173 179 181 
191 193 197 199 211 223 
227 229 233 239 241 251 
257 263 269 271 277 281 
283 293 307 311 313 317 
331 337 347 349 353 359 
367 373 379 383 389 397 
401 409 419 421 431 433 
439 443 449 457 461 463 
467 479 487 491 499 503 
509 521 523 541 547 557 
563 569 571 577 587 593 
599 601 607 613 617 619 
631 641 643 647 653 659 
661 673 677 683 691 701 
709 719 727 733 739 743 
751 757 761 769 773 787 
797 809 811 821 823 827 
829 839 853 857 859 863 
877 881 883 887 907 911 
919 929 937 941 947 953 
967 971 977 983 991 997 

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