prime numbers

[peppercolt]

I need help with a program that will take an integer and output whether or not the number is prime or composite.

[D_C]

There are much better ways to do this, but here's a quick lazy method.

bool isPrime(int input)
{
  int divisor;
  for(divisor = 2; divisor < (input/2); divisor++)
    if((input % divisor) == 0)
      return true;
  return false;
}

[sowmyth]

this is how i did in my school
#include<stdio.h>
main( ){
int n,i,flag=0;
printf("enter a number");
scanf("%d",&n);
for(i=2;i<n-1;i++){
if(n%i==0){
flag=1;
break;
}
}
if (flag==0)
printf("the number is prime");
}

[D_C]

Actually you only need to check 2, then the odd numbers from 3 to floor(sqrt(n)).
The reason is because if x, such that 1 < x < sqrt(number), is a factor, then (number/x) is a factor, and sqrt(number) <= number/x < number. Factors come in pairs, one will be less than or equal to sqrt(number), the other will be greater than or equal to sqrt(number).

[deepakwasake]

tel me how to write program on pallindrome?
tel me program which have output like
1
12
123
1234
12345