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

int main(int argc, char* argv[])
{
	static char str1[256] = "apple orange fruit cocktail.\0";
	static char str2[256] = "mama/\0";

	printf("string = %s\nword = %s\n",str1,str2);

	char* buf = str1; int count = 0;
	while ((buf = strchr(buf,' ')) != NULL)
	{
		int len = strlen(str2)+1;
		while (--len >= 0 && !(count % 2))
		{
			for (int q = strlen(str1)-1; q >= buf-str1; q--)
				str1[q+1] = str1[q];
		}

		if ((count % 2) == 0)
			memcpy((void*)++buf, (void*)str2, strlen(str2));

		buf+=strlen(str2)+1; count++;
	}

	if ((buf = strchr(str1,'.')) != NULL && !(count % 2))
	{
		*buf = ' ';
		memcpy((void*)++buf, (void*)str2, strlen(str2));
		if ((buf = strchr(buf,'/')) != NULL) *(buf+1) = '.';
	}

	printf("output = %s\n",str1);
	
    return 0;
}

string = apple orange fruit cocktail.
word = mama/
output = apple mama/ orange fruit mama/ cocktail.