Question : Write a C++ program to Check Whether Number is Prime or Not
?
Explain: C++ Question about check input from user then program tells us which given number is Prime or Not.
What is Prime Number with example ?
A number that is divisible only by itself and 1
For Examples : 2, 3, 5, 7, 11, 13,17,19 .. etc.
Solution:
/************************************************************
C++ Program for check Prime Number using if else
*************************************************************
***************** By cpplanguage.com *********************/
using namespace std;
int main()
{
int number, c;
bool Flag = true;
cout << "Enter a positive integer: ";
// Getting input Number
cin >> number;
// For Loop run until number divide by 2nd reminder 0 again and again , if true Flag will be set false. Prime number is which number that can divide only itself and 1 so if any time reminder not zero , flag not change , so flag true shows it is prime number , by default flag set to True
for(c = 2; c <= number / 2; ++c)
{
// check reminder within loop
if(number % c == 0)
{
Flag= false;
break;
}
}
if (Flag)
// Flag True It is a Prime number
cout <<number<<" is a prime number"<<endl;
else
// Flag False It is not a Prime number
cout <<number<<" is not a prime number"<<endl;
return 0;
}
Output:
