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  1. //Eric Bernal               CS1A                          Chapter 6, P. 375, #21
  2. //
  3. /*******************************************************************************
  4.  * DETERMINE PRIME NUMBER
  5.  * _____________________________________________________________________________
  6.  * This program determines if a given whole number is prime.
  7.  * _____________________________________________________________________________
  8.  * INPUT
  9.  * 	number	: The given whole number
  10.  *
  11.  * OUTPUT
  12.  * 	Whether the given number is prime
  13.  *
  14.  ******************************************************************************/
  15. #include <iostream>
  16. using namespace std;
  17.  
  18.  // FUNCTION PROTOTYPE
  19. bool isPrime(int num); 
  20.  
  21. int main() {
  22. //DATA DICTIONARY - INITIALIZE
  23. 	int number;  // INPUT   : A given whole number
  24. 	bool prime;  // OUTPUT  : Determine if a number is prime.
  25.  
  26. // Initialize Program Variables
  27. 	cout << "Enter a number to determine if it is prime: " << endl;
  28. 	cin >> number;
  29.  
  30. 	while (number < 1) {
  31. 		cout << "Please enter a number greater than 1: " << endl;
  32. 		cin >> number;
  33. 	}
  34.  
  35. // Determine If Given Number is Prime
  36. 	prime = isPrime(number);
  37.  
  38. 	if (prime) {
  39. 		cout << number << " is prime." << endl;
  40. 	} else {
  41. 		cout << number << " is not prime." << endl;
  42. 	}
  43.  
  44. 	return 0;
  45. }
  46.  
  47.  /*****************************************************************************
  48.   * The purpose of the following function is to determine if a whole number is
  49.   * prime or not.
  50.   *****************************************************************************/
  51.  
  52. bool isPrime(int num) {
  53. 	bool prime = true;
  54. 	// 1 and N are always divisors, so check for 2 through (N-1)
  55. 	for (int i = 2; i < num; i++) {
  56. 		// May be prime IF all prior numbers AND this number are not
  57. 		// 	divisors
  58. 		prime = prime && ((num % i) != 0);
  59. 	}
  60. 	return prime;
  61. }
  62.  
Success #stdin #stdout 0.01s 5276KB
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22
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Enter a number to determine if it is prime: 
22 is not prime.
https://ideone.com/GgSulM
Chapter 6, P. 375, #21
language:
C++ (gcc 8.3)
created:
1 year ago
visibility:
secret

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