Right truncable prime number code

/*
    Name: righttruncable.c
    Copyright:
    Author: Mr.Kindle
    Date: 08-12-22 22:22
    Description: This code print all righttruncable prime numbers between 100 & 999.

youtube: https://youtu.be/HuSXkh0IzDU
*/
#include<stdio.h>
int isprime(int );
int checkzero(int);
int isrighttruncable (int);

int main()
{
    int i,k=0;
    for (i=100;i<=999;i++)
         { if(isprime(i)==1 && checkzero(i)==1)
               { if (isrighttruncable(i)==1)
                      {printf("%d ",i);
                            k++;
                        }
            }
         }
        printf("\n\nTotal number of right-truncable prime number between 100 and 999 = %d\n",k);
    return 0;
}//main

int isprime (int n)
{ int i;
    for (i=2;i<=n/2;i++)
        if(n%i==0)
           return 0;
       if(n==1)
            return 0;
        else
           return 1;
}//isprime

int checkzero (int n)
{  if( n%100/10==0 || n%10==0)
       return 0;
    else
       return 1;
}//checkzero


int isrighttruncable (int n)
{ if(isprime(n/10)==1 && isprime(n/100)==1)
     return 1;
    else
       return 0;
}//isrighttruncable