In this example, you will learn to display all prime numbers between two numbers (entered by the user) using the function. The Prime numbers are numbers that are only divisible by themselves and 1.
Example: Print Prime Numbers (Using Function)
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#include <iostream> using namespace std; int checkPrimeNum(int); int main() { int n1, n2; bool flag; cout << "Enter the first positive integer: "; cin >> n1; cout << "Enter the second positive integer: "; cin >> n2; cout << "Prime numbers between " << n1 << " and " << n2 << " are: "; for(int i = n1 + 1; i < n2; ++i) { // If i is a prime number, flag will be equal to 1 flag = checkPrimeNum(i); if(flag) cout << i << " "; } return 0; } // user-defined function to check prime number int checkPrimeNum(int n) { bool flag = true; for(int j = 2; j <= n/2; ++j) { if (n % j == 0) { flag = false; break; } } return flag; } |
When you run the program, the output will be following:
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Enter the first positive integer: 5 Enter the second positive integer: 50 Prime numbers between 5 and 50 are: 7 11 13 17 19 23 29 31 37 41 43 47 |