This program checks whether a number is prime or not by dividing the entered number by all the numbers starting from 2 to the( entered number -1) and if the remainder is found to be 0 for any number then it will be displayed that the entered number is not a prime number.
But if none of the numbers have remainder as 0 then it will be displayed that the entered number is a prime number.
We will be displaying program which is compatible with Dev C++.
You can download dev c++ from here
Program Code:
#include<iostream.h>
#include<conio.h>
int main()
{
int a,b,c;
cout<<"Enter a number to check whether it's prime or not."<<endl;
cin>>a;
for(b=2;b<a;b++)
{
if(a==2 || a==1)
{
cout<<a<<" is a prime number.";
return(0);
}
if(a%b==0)
{
cout<<a<<" is not a prime number.";
getch();
return(0);
}
if(b==a-1)
{
cout<<a<<" is a prime number.";
}
}
getch();
}
Output:
