char str[256] = "this is a string";
	char revStr[256];
	char* words[256];
	int i = 0,j;
	char * pch;
	pch = strtok(str," ");
	while (pch != NULL)
	{
		words[i] = pch;
		i++;
		pch = strtok (NULL, " ");
	}
	strcpy(revStr,words[0]);
	for(j = 1 ; j < i ; j++)
	{
		strcat(revStr," ");
		strcat(revStr,words[j]);
	}
	printf("%s\n",revStr);