Dynamic memory allocation, name sorting, and searching.

Program 12(C++ I Lab).cpp

#include <stdio.h>
#include <iostream>

using namespace std;

#define LONG_NAME_SIZE 512

void main()
{
	int numNames = 0;
	char input[LONG_NAME_SIZE]; //Not infinite, but larger than anything the user will enter. If an "infinite" one is needed, look up std::string.
	char ** names = NULL; //Set array of pointers to NULL.
	while (true)
	{
		cout << "Enter name: ";
		cin.getline(input, LONG_NAME_SIZE); //Read entire line to input.

		if (strlen(input) == 0) //If empty.
			break; //Break out of while loop.
		char ** newNames = new char*[numNames + 1]; //Initialize new array of char pointers.

		for (int i = 0; i < numNames; i++) //Point all the old names to the new names. (strcpy and such is not needed because this is just using pointers.)
			newNames[i] = names[i];

		if (names != NULL) //If names are set yet.
			delete [] names; //Delete ALL the names.
		names = newNames; //Point names to newNames.

		//Point the newest name to a new character array of the length of the input + 1 (to include null terminator).
		names[numNames] = new char[strlen(input) + 1];
		//Copy input to the name.
		strcpy(names[numNames], input);
		//Increment the number of names.
		numNames++;
	}
	cout << "Done with names. Sorting." << endl;
	//Sort!
	for (int i = numNames - 1; i >= 0; i--) //Loop through all names, starting with the last one, and looping down to (and including) 0.
	{
		for (int j = 0; j < i; j++) //Loop through all names < i.
		{
			int len = strlen(names[j]); //Get the length of the name at j's location.

			if (len > strlen(names[i])) //Make sure that we're not looping past the length of the name at i's location.
				len = strlen(names[i]);
			for (int k = 0; k < len; k++) //Loop from the first character to len.
			{
				if (tolower(names[j][k]) > tolower(names[i][k])) //If the character at k within names[j] is greater than the character at k within names[i]
				{
					//The tolower function gets the lowercase version of the character.
					char * temp = names[j]; //Point temporary to names[j].
					names[j] = names[i]; //Set the pointer at names[j] to the address at names[i].
					names[i] = temp; //Set the pointer at names[i] to the address of temp.
					//Break out of the k loop.
					break;
				}
				else
					break; //Break out of the k loop because the name at i does not belong before the name at j.
			}
		}
	}

	cout << "Sorted: " << endl;
	//Print all the names.
	for (int i = 0; i < numNames; i++)
		cout << i << " " << names[i] << endl;

	//Loop and get search string.
	while (true)
	{
		cout << "Enter a string to find: ";
		//Read in entire input line.
		cin.getline(input, LONG_NAME_SIZE);

		if (strlen(input) == 0) //If empty.
			break; //Break out of while loop.

		bool found = false; //Set (is) found to false, so we can know if we found it after the loop.
		for (int i = 0; i < numNames; i++)
		{
			//If there is no difference between the input and names[i].
			if (strcmp(input, names[i]) == 0)
			{
				found = true; //Set (is) found and print the index.
				cout << "Found search string at " << i << endl;
				break; //Break out of search.
			}
		}
		if (!found) //If not found.
			cout << "Search string not found." << endl; //Let the user know of our sorrow.
	}
	//Everybody clean up!
	cout << "Done! Cleaning up..." << endl;

	//Loop through all names.
	for (int i = 0; i < numNames; i++)
		delete [] names[i]; //Delete the array names[i] points to.
	delete [] names; //Delete the array of arrays.
}