C++ program to find a number is prime or not?
Algorithm:
Input = number
set counter=0;
set i=0 to i<=number
if(number%i==0)
counter=counter+1;
i=i+1;
if(counter == 2)
print"number is prime";
else
print "number is not prime";
exit;
Approach to solve:
Input = 5;
number%i=5%1=0
5%2=1
5%3=2
5%4=1
5%5=0
counter=2
so, it will print number is prime.
Input =4
number%i=4%1=0
4%2=0
4%3=1
4%4=0
counter=3
so, it will print number is not prime.
Program:-
#include<iostream>
using namespace std;
//function for prime number
int prime(int num){
int count=0;
if(num==1){
return 0;
}
for(int i=1; i<=num; i++){
if(num%i==0)
count++;
}
if(count==2){
cout<<"Number is Prime ";
}
else
{
cout<<"Number is not prime ";
}
}
int main(){
int num1;
cout<<"Enter any number:";
cin>>num1;
prime (num1); //function calling
return 0;
}
Output:-
Enter any number:3
Number is prime
Enter any number:88
Number is not prime
HAPPY CODING...