#include<stdio.h>
#include<string.h> // for strlen
#include<stdlib.h> // for malloc and free

// This is the same as strcpy which is in string.h
void make_copy(char* dest, char *src){
	int i;
	for(i = 0; src[i]; i++)
		dest[i] = src[i];
	dest[i] = 0;
}

void double_word_ubuf(char *word, char *result_place){
	make_copy(result_place, word);
	make_copy(result_place + strlen(word), word);
}

char* double_word_sbuf(char *word){
	static char return_space[1024];
	if(strlen(word) > 511){
		printf("This function does not support that length\n");
		return 0;
	}
	make_copy(return_space, word);
	make_copy(return_space + strlen(word), word);
	return return_space;
}

int main(){
	char array_one[40] = "goose";
	char array_two[40];
	make_copy(array_two, array_one);
	printf("Array:  %s\n", array_two);
	char *doubled = double_word(array_one);
	printf("Our copy:  %s\n", doubled);
	printf("Our copy:  %s\n", doubled);
	free(doubled);

	make_copy(array_two, "elephant moose mouse snail ");
	doubled = double_word(array_two);
	printf("Longer string doubled:  %s\n", doubled);
	free(doubled);

	make_copy(array_one, "elk deer goat ");
	double_word_ubuf(array_one, array_two);
	printf("Doubled array:  %s\n", array_two);

	char *dbant = double_word_sbuf("ant ");
	char *dbspider = double_word_sbuf("spider ");
	printf("dbant = %p\n", dbant);
	printf("dbspider = %p\n", dbspider);

	printf("dbant = %s\n", dbant);
	printf("cat types:  %s\n", double_word_sbuf("tiger lion cougar bobcat "));
	printf("dbant = %s\n", dbant);

	return 0;

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

// Prototype for the custom function called in the assembly
void make_copy(char *dest, const char *src);


char* double_word(char* word){
	char *return_space = malloc(strlen(word) * 2 + 1);
	make_copy(return_space, word);
	make_copy(return_space + strlen(word), word);
	return return_space;
}