Question

In this homework, you will implement a simple version of the game Battleship, in which the player tries to destroy ships hidden on a map using a system of coordinates. In this program, the map will be represented by a 4x4 matrix of integers. A 1 in the matrix represents the presence of a ship. There are 3 ships hidden in the map, for example 0 10 0 1 000 0000 10 00 Your task is to create a function battleship) that takes as argument the boolean map and a string of coordinates. The coordinates are represented by a pair of a letter (for columns) and a number (for rows), as illustrated below A B C D 11 0 1 0 0 1 0 0 0 0 00 0 4] 1 0 0 0 For example, an input string could be A1 A2 B4", or "B1 A2 A4" (the winning string in this example). The function must determine if the string entered is a winning string and print the following messages: You won the battle! If all targets have been hit, or <n> targets remaining. You lost! Where n is the number of ships that were not hit. Additionally, the function will print the following message and quit the game if invalid coordinates (letters or numbers) are entered: Invalid coordinates entered. Game over! All messages must end on a new line. In the main function, you should read from standard input the name of the file where the map is saved and the coordinates to be tested, in the following format: mapfile.txt A1 A2 B4

I haven't code in awhile and would like some help getting back on my feet. Need to code this in C++. Thank you!

Answer 1

Here is the code with comments:

-------------------------------------------------------------------------------

#include <iostream>

#include <fstream>

using namespace std;

void battleship(bool map[4][4], string coordinates){

  //finding indices from the coordinates using some ascii math

  int x1 = coordinates[0] - 'A';

  int y1 = coordinates[1] - '1';

  int x2 = coordinates[3] - 'A';

  int y2 = coordinates[4] - '1';

  int x3 = coordinates[6] - 'A';

  int y3 = coordinates[7] - '1';

  //checking for valid coordinates

  bool validCoord = true;

  if(x1 < 0 || x1 > 3)validCoord = false;

  if(x2 < 0 || x2 > 3)validCoord = false;

  if(x3 < 0 || x3 > 3)validCoord = false;

  if(y1 < 0 || y1 > 3)validCoord = false;

  if(y2 < 0 || y2 > 3)validCoord = false;

  if(y3 < 0 || y3 > 3)validCoord = false;

  if(!validCoord) {

      cout << "Invalid coordinates entered. Game Over!\n";

      return;

  }

  else {

      //count how many targets remaining

      int count = 3;

      if(map[y1][x1])count--;

      if(map[y2][x2])count--;

      if(map[y3][x3])count--;

      if(count > 0){

          cout << count << " targets remaining. You lost!" << endl;

          return;

      }

      else {

          cout << "You won the battle!" << endl;

      }

  }

}

int main(){

  string filename;

  cin >> filename;

  //taking input from given file

  ifstream in(filename);

  bool map[4][4];

  for(int i = 0; i < 4; ++i){

      for(int j = 0; j < 4; ++j){

          in >> map[i][j];

      }

  }

  //taking input of coordinates

  string coordinates;

  cin.ignore();//ignoring the newline character.

  getline(cin, coordinates);

  //calling required function

  battleship(map, coordinates);

}

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Sample IO:

E mapfile.txt x main.cpp 1 010 0 2 100 O 3 000 0 1000 5 Terminal File Edit View Search Terminal Help [unseen@pc]01:35 PM_$ ~/prog/CPP - ./main mapfile.txt A1 A2 B4 2 targets remaining. You lost! [unseen@pc]01:36 PM_$ ~/prog/CPP - ./main mapfile.txt B1 A2 A4 You won the battle! [unseen@pc]01:36 PM_$ ~/prog/CPP ./main mapfile.txt A0 A1 A2 Invalid coordinates entered. Game Over! [unseen@pc]01:36 PM_$ ~/prog/CPP