Question

write a program to check whether a no. is prime or not with explanation

Answer 1

in which language -java or basic?
for java,

class prime
{
void main(int n)
{
int no_fac,;// no_fac represents no. of factors
int lo_va;// lo_va represents loop variable
for(lo_va=1;lo_va<=n;lo_va++)
{
no_fac=0;// no. of factors is initially zero
if(n%lo_va==0)// this means "if lo_va is a perfect factor of n"
no_fac++;//no. of factors is increased by 1
}
if(no_fac==2)//only a prime no. has 2 factors, rest all have more than 2
System.out.println("It is a prime no.");
else
System.out.println("It is not a prime no.");
}
}

Answer 2

#include<iostream.h> 
int main() 
{ 
int num; 
cout << "Enter a number "; 
cin >> num; 
int i=2; 
while(i<=num-1) 
{ 
if(num%i==0) 
{ 
cout << "\n" << num << " is not a prime number."; 
break; 
} 
i++; 
} 
if(i==num) 
cout << "\n" << num << " is a prime number."; 
return 0; 
}