Question

I have a text file containing the following information:

# Map

# Small islands with treasure in the NW corner and start in the SE corner.

M

5

o$...

oo...

#..o.

..oo.

....@

I want to read in the file but want to ignore the comments at the top (they begin with #). There can be infinite amount of comments. I want to store the letter (M) in a char variable, and the number as the map size. The following characters represent a treasure map, and I want to read that into a vector of vectors. How should the code look to accomplish this? I am writing the code in C++.

Answer 1

There is only one assumption I am making: (Any number of) Comments will appear only in the top. When first character M appears there will be no comments after that.

• Below is the implementation in C++:

#include<bits/stdc++.h>
using namespace std;

int main(){
   ifstream fread;
   fread.open("input.txt"); //Put the exact location of file to open in quoted text.
   string line;
   string arr[1000];       // Assign the array of size of appropriate length othewise data overflow may occur.
   int i=0;
   bool comments=true;       //This boolean is used to indicate that there are still comments in the text being read.
   while(fread.is_open() && getline(fread,line)){
       //Ignore the comments at the top, they start with the symbol '#'.
       if(line[0]=='#' && comments==true){
           continue;
       }
       else{
       comments=false;
       arr[i++]=line;

       }
   }
   fread.close();

   //Reading character M
   char M=arr[0][0];
   cout<<M;

   //Reading next integer size: size of map. stringstream object is used to cast string object to integer.
   //Note: If you are using cpp11 and higher you can use stoi() or atoi() directly for string to int conversion.
   stringstream obj(arr[1]);
   int size;
   obj>>size; //stringstream casts string to integer.
   cout<<"Size of the map: "<<size;

   //reading the map from arr.
   vector<vector<char> > Map(size);
   for(int j=0;j<size;j++){
       Map[j]=vector<char>(size);
       for(int k=0;k<size;k++)
           Map[j][k]=arr[j+2][k];
   }
  
   cout<<"\n\nThe map is:\n";
   for(int j=0;j<size;j++)
   {
       for(int k=0;k<size;k++)
           cout<<Map[j][k];
       cout<<endl;
   }
  

   //So the M variable,size variable and Map variable are the required data.
   return 0;
}

• Below is the screenshot of desired output:

Thank You, hope that helps!