#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *concatWords(char *w1, char *w2, char *w3);
void initWords(char *w1, char *w2, char *w3);
void initWord(char **w, const char *wordNumber);

int main(int argc, char **argv)
{
   char words1[10] = {'\0'};
   char words2[10] = {'\0'};
   char words3[10] = {'\0'};
   initWords(words1, words2, words3);
   return 0;
}

char *concatWords(char *w1, char *w2, char *w3)
{
   int i;
   char *w4;
   int totalSize = strlen(w1) + strlen(w2) + strlen(w3) + 1;
   w4 = (char *)malloc(totalSize);

   if (!w4)
   {
      printf("Memory allocation failed, try again!\n");
      return NULL;
   }

   strcpy(w4, w1);
   strcat(w4, w2);
   strcat(w4, w3);

   printf("w4 = %s\n", w4);
   return w4;
}

void initWords(char *w1, char *w2, char *w3)
{
   initWord(&w1, "first");
   initWord(&w2, "second");
   initWord(&w3, "third");

   char *result = concatWords(w1, w2, w3);
   if (!result)
      return;

   printf("result = %s\n", result);
   free(result);
}

void initWord(char **w, const char *wordNumber)
{
   printf("Please insert the %s word that it's max length is 10 letters:\n", wordNumber);
   scanf("%10s", *w);
   printf("You chose to insert the word: %s", *w);
}