How to merge arrays passed to a function with variable parameters - c

Question

Ive been researching all day on how to merge arrays, and make functions with variable parameters. Then it got me thinking, 'can't I combine the two?'. I came up with this function. According to my understanding it should work, but I'm getting errors. Can anyone tell me what I'm doing wrong?
#include <stdio.h>
#include <stdarg.h>
char* merge(int num, ...)
{
va_list list;
char arr[9] = {0};
char *temp;
int i;
int j;
int k=0;
va_start(list,num);
for(i=0;i<num;i++)
{
temp = va_arg(list,char[]);
j = 0;
while(temp[j] != 0x00)
{
arr[k] = temp[j];
j++;
}
k++;
}
va_end(list);
return arr;
}
int main()
{
char data_1[] = "my";
char merged_array[9] = "legs";
int n=0;
//merged_array = merge(1, data_1);
while(merged_array == 0x00)
{
printf("%s\n",merged_array[n]);
n++;
}
}

Answer 1

Perhaps this will help get you started:
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
char* merge(char *arr, int num, ...)
{
va_list list;
int i;
va_start(list,num);
for(i=0;i<num;i++)
strcat(arr, va_arg(list,char *));
va_end(list);
return arr;
}
int main()
{
char data_1[] = "my";
char merged_array[9] = "legs";
merge(merged_array, 1, data_1);
printf("%s\n", merged_array);
return(0);
}