Q2. Check if a number is a prime number
Q2. Check if a number is a prime number using a function
Note on booleans in C++
boolean variables can be declared using the bool keyword
For example,
bool bPrime = true;
Read the following code carefully to understand how to use booleans in C++
Solution
/* primetester.cpp */ #include <iostream> using namespace std; //function prototype declaration bool isPrime(int number); int main() { int num = 0; cout << "Enter a number:"; //display prompt to the user cin >> num; //read the number from the keyboard bool bPrime = isPrime(num); //call the isPrime function cout << "bPrime:" << bPrime << endl; //if false print 0 - if true prints 1 if(bPrime == true) //print whether the number is prime or not cout << num << " is a prime number" << endl; else cout << num << " is not a prime number" << endl; system("pause"); //this stops the output window from closing automatically } bool isPrime(int number) { bool bPrime = true; //assume that the number is prime //now test if the number is actually a prime number for (int i = 2 ; i < number ; i++) { if (number % i == 0) { //number is not prime - set bPrime to false bPrime = false; //and come out of the loop using break break; } } return bPrime; }
page revision: 1, last edited: 09 Sep 2009 10:08