Not able to take input of numbers from notepad in my code

Question

My code is (using Atom):

Kindly note all the errors have been removed, but the output is wrong. At the end of the question, the output is listed.

#include<iostream>
#include<fstream>

using namespace std;

int main()
{
  char ch ;
  int a, arr[2], i=0;
  ifstream f(“num.txt”);
  while(!f.eof())
  {
    f>>ch;
    arr[i]=a;
  }
  f.close();
  for(int i = 0 ; i<3 ; i++)
  {
    cout<<a[i]<<'\n';
  }
  return 0;
}

The data of 'num.txt' is '123'.

Error:
C:\Users\sy304\Documents\CPP\num_text.cpp:10:14: error: stray '\342' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp:10:15: error: stray '\200' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp:10:16: error: stray '\234' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp:10:24: error: stray '\342' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp:10:25: error: stray '\200' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp:10:26: error: stray '\235' in program
ifstream f(“num.txt”);
^
C:\Users\sy304\Documents\CPP\num_text.cpp: In function 'int main()':
C:\Users\sy304\Documents\CPP\num_text.cpp:10:17: error: 'num' was not declared in this scope
ifstream f(“num.txt”);
^~~
C:\Users\sy304\Documents\CPP\num_text.cpp:19:14: error: invalid types 'int[int]' for array subscript
cout<<a[i]<<'\n';
^

I am new to Atom. How can I get the solution for these errors?

Output:

51
1982955789
859839168

Answer 1

You are indexing the variable a, which is an int, not an array. Also, in the while loop, you are only accessing the first element of array arr (because i is 0), and you are assingnig allways a's value, that's not set anywhere. You should check f.fail() after reading into ch or at least do something like

std::array<int, 2> arr;

for(int i = 0; (std::cin >> ch) && i < arr.size(); ++i) {
    arr[i];
}

If you don't know in advance how many numbers you have to read use std::vector instead and push_back the values.