C++ Programming Code Examples
C++ > Mathematics Code Examples
program in C++ to check whether a number is prime or not.
/* program in C++ to check whether a number is prime or not. */
#include <iostream>
using namespace std;
int main()
{
int num1, ctr = 0;
cout << "\n\n Check whether a number is prime or not:\n";
cout << "--------------------------------------------\n";
cout << " Input a number to check prime or not: ";
cin>> num1;
for (int a = 1; a <= num1; a++)
{
if (num1 % a == 0)
{
ctr++;
}
}
if (ctr == 2)
{
cout << " The entered number is a prime number. \n";
}
else {
cout << " The number you entered is not a prime number. \n";
}
}
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