Given a number and we need to find whether a given number is prime or not.
So what is prime Number?
Prime number is a number that is divisble by itself and 1 .
for example-2,3,5,7,11 …. are prime number because they are divisble by 1 and itself. .
Examples:
input:5
output:true
input:7
output:true
input:10
output:false#include<iostream>
using namespace std;
int main()
{
int num;
cout<<"Enter a number to check Number is prime or not : "<<endl;
cin>>num;
bool flag=0;
for(int i=2;i<=num/2;i++)
{
if(num%i==0)//checking whether number have any other divisor
{
flag =1;//if divisor present then number is not a prime number
break;
}
}
if(flag==0)
{
cout<<num<<" is a prime number"<<endl;
}
else
{
cout<<num<<" is not a prime number"<<endl;
}
}
Output
Enter a number to check Number is prime or not : 5 5 is a prime number
Expected Time Complexity-O(N) where N is the given number.
Expected space Complexity-O(1).
