C++ Confusion. Reading Integer From Text File. Convert to ASCII

Question

I am learning C++ for the first time. I have no previous programming background.

In the book I have I saw this example.

#include <iostream>

using::cout;
using::endl;

int main()
{
    int x = 5;
    char y = char(x);

    cout << x << endl;
    cout << y << endl;

    return 0;
}

The example makes sense: print an integer and the ASCII representation of it.

Now, I created a text file with these values.

48
49
50
51
55
56
75

I am writing a program to read this text file -- "theFile.txt" -- and want to convert these numbers to the ASCII value.

Here is the code I wrote.

#include <iostream>
#include <fstream>

using std::cout;
using std::endl;
using std::ifstream;

int main()
{
    ifstream thestream;
    thestream.open("theFile.txt");

    char thecharacter;  

    while (thestream.get(thecharacter))
    {
        int theinteger = int(thecharacter);
        char thechar = char(theinteger);
        cout << theinteger << "\t" << thechar << endl;
    }


    system ("PAUSE");
    return 0;
}

This is my understanding about the second program shown.

• The compiler does not know the exact data type that is contained in "theFile.txt". As a result, I need to specify it so I choose to read the data as a char.
• I read the each digit in the file as a char and converted it to an integer value and stored it in "theinteger".
• Since I have an integer in "theinteger" I want to print it out as a character but char thechar = char(theinteger); does not work as intended.

What am I doing incorrect?

Answer 1

You are reading one char at a time from the file. Hence, if your file contains:

2424

You will first read the char "2" from the file, convert it to an int, and then back to a char, which will print "2" on cout. Next round will print "4", and so on.

If you want to read the numbers as full numbers, you need to do something like:

int theinteger;
thestream >> theinteger;
cout << char(theinteger) << endl;

Answer 2

You are reading char by char, but you really (I think) want to read each sequence of digits as an integer. Change your loop to:

int theinteger; 
while (thestream >> theinteger )
{
    char thechar = char(theinteger);
    cout << thechar << endl;
}

+1 For a very nicely formatted & expressed first question, BTW!