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If I input a number, how can I output all the numbers to that input number and check if it is prime?

I also want to know how can I (for every number) output the numbers that evenly divide?

26th Feb 2017, 10:18 PM
Poppy
Poppy - avatar
1 Antwort
+ 1
#include<iostream> int main() { int user_input, x; std::cout << "This program will check for prime numbers\n"; std::cout << "Please enter an integer upper bound: "; std:: cin >> user_input; //this for loop goes through each number up to the user input upper boundary for (int i = 2; i < user_input; i++){// i starts at 2 because the numbers 1 and 2 are by default prime numbers. x = 0;//a variable to check if a number is prime. If it gets set to 1 the number is not prime. for (int j = 2; j < i; j++){//this loop divides the number by 2 up to itself and if the remainder is 0 sets x = 1. if (i%j == 0){ x = 1; break; } } if (x == 0){//if the x = 1 flag is never set the number is prime. std::cout << i << " is a prime number\n"; } } return 0; } Edit & Run edit.. guess i could add some comments to explain it sec.
26th Feb 2017, 10:30 PM
Mohamed Abdalla
Mohamed Abdalla - avatar