Prime number program in C using recursion?

Answer 1

//Program to check number is prime or not using recursive function

#include<stdio.h>

#include<stdlib.h>

void prime(int num,int count)

{

if(count<num)

{

if(num%count==0)

{

printf("%d is not Prime number\n",num);

goto exit;

}

count += 1;

if(count<num)

{

prime(num,count);

}

}

if(num==count)

{

printf("%d is a Prime Number\n",num);

}

exit:

return 0;

}

int main()

{

system("cls");

int gvar;

printf("Enter the number = ");

scanf("%d",&gvar);

prime(gvar,2);

printf("\nashokakhil@gmail.com\n");

system("PAUSE");

return 0;

}

I think this can be another solution

#include<stdio.h>

#include<conio.h>

int prime(int);

main()

{

int i=1,r;

clrscr();

r=prime(i);

if(r==1)

printf("\n\n\tNo is prime ");

getch();

}

int prime(int i)

{

int n=1,ans,flag=1;

i++;

ans=n%i;

if(ans==0)

{

printf("\t\t\n\nNo is not prime");

flag=0;

return flag;

}

if((i!=n-1)&&(n!=1))

flag=prime(i);

return flag;

}