Can someone explain what is happening in the C++ bolded/italicized code. #includ
ID: 3721464 • Letter: C
Question
Can someone explain what is happening in the C++ bolded/italicized code.
#include <fstream>
#include <iomanip>
#include <iostream>
using namespace std;
const int ROWS = 8;
const int COLS = 8;
//Character map for user moves
const char UP = 'w';
const char LEFT = 'a';
const char DOWN = 's';
const char RIGHT = 'd';
//Character map for tile types
const char START = 'S';
const char FINISH = 'F';
const char SPACE = ' ';
const char WARP_LEFT = '<';
const char WARP_RIGHT = '>';
const char WARP_UP = '^';
const char WARP_DOWN = 'v';
const char BOX = 'X';
const char CHOICE = 'C';
const char TRACK = 'o';
//Character map for tile types
const char PLAYER = 'A';
//-----------------------------------------------------------------------------------
// Name: init
// Purpose: This function opens a file, reads the dimensions of the map, and loads a map into the 2D array
// It prints an error message to cerr if the file cannot be opened.
// Any '.' in the map file are converted to spaces in the array.
// Parameters: filename, const string, the file holding the map
// map, 2D array of characters, the map filled in from the file
// path, 2D array of characters, sets the path to the start location
// playerRow, int, the player row location (updated by fn)
// playerCol, int, the player col location (updated by fn)
// Returns: void
//-----------------------------------------------------------------------------------
void init(const string filename, char map[ROWS][COLS], char path[ROWS][COLS], int &playerRow, int &playerCol)
{
//Open the file
ifstream din(filename.c_str());
if (!din)
cerr << "Could not open " << filename << " .";
else
{
//Set the player location
playerRow = ROWS - 1;
playerCol = 0;
//Iterate over the rows and the columns
for(int row = 0; row < ROWS; row++)
for(int col = 0; col < COLS; col++)
{
//Read the data into the map
din >> map[row][col];
if (map[row][col] == '.')
map[row][col] = SPACE; //convert from the . in the file to SPACE in the array
//Init the path with the START and FINISH locations
//Fill the rest of the path with spaces
if (map[row][col] == START || map[row][col] == FINISH)
path[row][col] = map[row][col];
else
path[row][col] = SPACE;
}
//Close the file
din.close();
}
}
//-----------------------------------------------------------------------------------
// Name: print
// Purpose: This function prints the map to the screen
// Parameters: map, const 2D array of characters, stores the map
// path, const 2D array of characters, stores the player path
// playerRow, const int, the player row location
// playerCol, const int, the player col location
// Returns: void
//-----------------------------------------------------------------------------------
void print(const char map[ROWS][COLS], const char path[ROWS][COLS], const int playerRow, const int playerCol)
{
cout << "Here is the map and path. The legend is: "
<< " S - start, F - finish "
<< " < - warp left, > - warp right, ^ - warp up, v - warp down "
<< " X - box, C - choice "
<< " A - your location, o - your track ";
// print the map top border
cout << " MAP: PATH: -";
for(int col = 0; col < COLS; col++)
cout << "----";
cout << " -";
// print the path top border
for(int col = 0; col < COLS; col++)
cout << "----";
cout << " ";
// print the map contents and the path
// replace any . stored in the array with spaces on screen to look nicer
for(int row= 0; row < ROWS; row++)
{
// print the map
cout << "|";
for(int col = 0; col < COLS; col++)
{
if (playerRow == row && playerCol == col)
cout << setw(2) << PLAYER << setw(2) << " |";
else
cout << setw(2) << map[row][col] << setw(2) << " |";
}
// print the path
cout << " ";
cout << "|";
for(int col = 0; col < COLS; col++)
{
if (playerRow == row && playerCol == col)
cout << setw(2) << PLAYER << setw(2) << " |";
else
cout << setw(2) << path[row][col] << setw(2) << " |";
}
// print the map bottom border
cout << " -";
for(int col = 0; col < COLS; col++)
cout << "----";
// print the path bottom border
cout << " -";
for(int col = 0; col < COLS; col++)
cout << "----";
cout << " ";
}
cout << " ";
}
//-----------------------------------------------------------------------------------
// Name: gameOver
// Purpose: This function checks to see if the game is over, i.e., the player
// has reached the FINISH tile.
// Parameters: ???
// Returns: true if the player has reached the FINISH tile; false otherwise
//-----------------------------------------------------------------------------------
// ??? gameOver(???)
bool gameOver(char map[ROWS][COLS], int r, int c)
{
if (map[r][c] == FINISH)
return true;
else
return false;
}
//-----------------------------------------------------------------------------------
// Name: getMove
// Purpose: This function gets the next move direction from the user.
// It keeps asking until a valid direction is entered
// Parameters: ????
// Returns: move, char, the valid character entered
//-----------------------------------------------------------------------------------
// ??? getMove(???)
char getMove()
{
char c;
cout << "Enter a move(w,a,s,d) or 'q' to save: ";
cin >> c;
while (c != UP && c != LEFT && c != DOWN && c != RIGHT)
{
cout << "Enter a move (w,a,s,d) or 'q' to save: ";
cin >> c;
}
return c;
}
void getnewRowCol(char map[ROWS][COLS], char path[ROWS][COLS], int r, int c, char move, int &newRow, int &newCol, bool update)
{
if (move == UP)
{
newRow = r-1;
newCol = c;
}
else if (move == LEFT)
{
newRow = r;
newCol = c-1;
}
else if (move == DOWN)
{
newRow = r + 1;
newCol = c;
}
else
{
newRow = r;
newCol = c + 1;
}
if (update)path[newRow][newCol] = TRACK;
}
//-----------------------------------------------------------------------------------
// Name: legal
// Purpose: This function checks whether or not the user can make the move requested
// by the user. Illegal moves are those that would move the user off the map
// or land the user in a box.
// Parameters: ???
// Returns: true if the user can make the move, false otherwise
//-----------------------------------------------------------------------------------
// ??? legal(???)
bool legal(char map[ROWS][COLS], char path [ROWS][COLS], int r, int c, char move)
{
int newRow, newCol;
getnewRowCol(map, path, r, c, move, newRow, newCol,false);
if (newRow < 0 || newCol < 0 || newRow >= ROWS || newCol >= COLS || map[newRow][newCol] == BOX)
return false;
else
return true;
}
//-----------------------------------------------------------------------------------
// Name: makeMove
// Purpose: This makes the move selected by the user.
// It assumes that the move has already been checked and is legal.
// It updates the player' location and adds that location to the PATH.
// It then examines the tile the user just moved to to see if it causes any
// side effects.
// If the new tile is a space tile, keep going.
// (i.e., warping to another location); if so, it then
// updates the player location again
// Parameters: ???
// Returns: void
//-----------------------------------------------------------------------------------
// ??? makeMove(???)
void makeMove(char map[ROWS][COLS], char path[ROWS][COLS], int &r, int &c, char &move)
{
getnewRowCol (map, path, r, c, move, r, c, true);
while (map[r][c] != CHOICE && map[r][c] != FINISH)
{
if (map[r][c] == WARP_UP)
{
if (legal(map, path, r, c, UP))
{
move = UP;
getnewRowCol(map, path, r, c, move, r, c, true);
}
}
else if (map[r][c] == WARP_DOWN)
{
if (legal(map, path, r, c, DOWN))
{
move = DOWN;
getnewRowCol(map, path, r, c, move, r, c, true);
}
}
else if (map[r][c] == WARP_RIGHT)
{
if (legal(map, path, r, c, RIGHT))
{
move = RIGHT;
getnewRowCol(map, path, r, c, move, r, c, true);
}
}
else if (map[r][c] == WARP_LEFT)
{
if (legal(map, path, r, c, LEFT))
{
move = LEFT;
getnewRowCol(map, path, r, c, move, r, c, true);
}
}
else if (map[r][c] == SPACE)
{
if (legal(map, path, r, c, move))
{
getnewRowCol(map, path, r, c, move, r, c, true);
}
}
}
}
//-----------------------------------------------------------------------------------
// Name: load PAIRS ONLY
// Purpose: This loads a saved game from file(s).
// It writes an error message to cerr if the file cannot be opened.
// It opens the file and sets playerRow and playerCol.
// It also fills in the map and the path matrices from the file.
// Any '.' in the map or path files are converted to spaces in the array.
// Parameters: ???
// Returns: void
//-----------------------------------------------------------------------------------
// ??? load(???)
void load()
{
}
//-----------------------------------------------------------------------------------
// Name: save PAIRS ONLY
// Purpose: This saves a game to a file.
// It opens the file and writes playerRow and playerCol.
// It prints an error message to cerr if the file cannot be opened.
// It also writes the map and the path matrices to the file.
// Any spaces in the map or path arrays are converted to '.' in the file so they are visible.
// Parameters: ???
// Returns: void
//-----------------------------------------------------------------------------------
// ??? save(???)
void save()
{
}
int main()
{
//Declare two 2D char arrays for the map and path
//Each array should have ROWS rows and COLS cols
char map[ROWS][COLS];
char path[ROWS][COLS];
//Declare two ints to keep track of the player location, their row and col in the map
int r, c;
//Ask the user whether or not they want a new game or to load a game (PAIRS)
//Initialize the map and path and player location for a new game from file "map.txt"
//or set them based on a save file
const string filename = "map.txt";
init(filename, map, path, r, c);
//While we have not won the game by reaching the top right corner
//do
while (!gameOver(map, r, c))
{
//Print map and path
print(map, path, r, c);
//Get a valid type of move from the player
char move = getMove();
//If the user wants to quit, save the game and set done to true
if (move == 'q')
{
save();
break;
}
//Check the move to see if it is legal
bool check = legal(map, path, r, c, move);
//If the move is legal, make it
//Check to see if the user has won after the move
if (check)
{
makeMove(map, path, r, c, move);
}
}
//while(the user has not won and the user has not quit
//If the player won the game, print a congratulatory message
cout << " ------------------------------------------- " << endl;
cout << " CONGRATULATIONS! You found the Silph Scope. "<<endl;
cout << " ------------------------------------------- " << endl;
print(map, path, r, c);
return 0;
}
Explanation / Answer
Hi, I explained your bolded text in comment itself hope you understand. If any part of code you will not then free to ask in comment. Thanks
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