Collatz conjecture using C programming

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <sys/wait.h>

int main()
{
char c,num[10];
int n,len,i;
while(1)
{
printf("\nWhat is your number");
gets(num);//Read input from console
if(strcmp(num,"q")==0)// Quit if input is q
exit(0);
n=atoi(num);// String to number conversion
if(n>2)// Wrong input checking
{
        collatz(n);// Function calling
}
else
{
        printf("enter valid input...\n");
}

}
return 0;

}

int collatz(int i)// Called Function
{

pid_t child_pid, wpid;

int status = 0;

        if ((child_pid = fork()) == 0)// Child process creation

{

while(i != 1){

printf("%d\t", i);

if(i%2 == 0){// If n is even

i /= 2;

}

else{// if n is odd

i = 3*i + 1;

}

}

printf("1\n");
exit(1);

}
while ((wpid = wait(&status)) > 0)

{

printf("Child process exited\n");

}

return;
}