char and '0' comparison in c++ not giving wanted results

Question

i am having a binary value read from file and have to make comparison whether its a 1 or 0 but when i try to compare

char ch;
while(!in.eof()){
    in.get(ch);
    if(ch=='0') count0++;
}

The above code is not executing even when ch='0'

if(ch=='1') count1++;

that too is not giving me correct answer how these can be compared? it has to do something with the ascii coding or something?

From a comment: The content of the file is 01101111111111111100000000 just like that. It's a .txt file

Is the file you read a binary file, or is it a text file containing the characters `'0'` and `'1'`? — Some programmer dude, Sep 26 '13 at 10:47
Also, you should not do `while (!in.eof()) { ... }`, as the EOF flag will not be set until you try to read once you're already am at the end of the file. Instead do `while (in.get(ch)) { ... }` — Some programmer dude, Sep 26 '13 at 10:48
You might want to edit your question to include an example of the file you try to read from, and maybe more code for context (preferably a [SSCCE](http://sscce.org/)). — Some programmer dude, Sep 26 '13 at 10:56
what is the type of `ch`? The name ch suggests that it is a `char`, in which case your program should work, but if it is an int, than the ascii '0' is converted to the value 0. — stefaanv, Sep 26 '13 at 11:01
@stefaanv Nope, the ASCII for `'0'` is and will always be `48`. As long as the type used is an integer type it will always be that. — Some programmer dude, Sep 26 '13 at 11:02
Use a debugger, break at line `if(ch=='0') count0++;`, tell us what's the value of `ch`. — Michael M., Sep 26 '13 at 12:07

score 0 · Answer 1 · edited May 23 '17 at 12:20

Your question leaves some space for interpretation.

You say that your file contains '1' and '0'. All files contain ones and zeros. Computers contain nothing more than ones and zeros (joke!).

Since you say that you have a binary file, I assume that what you try to ask is how to read the contents of the file bit by bit. Is that what you are asking?

If not, then you already have answers in the comments. Discard the rest of this message.

If yes, you'd want to first read byte by byte (i.e.: char by char) as you are doing and then iteratively apply some masks upon the byte to see whether at the given position in the byte there is a one or a zero ( this - how to convert a char to binary? - might help ).

no the content of the file is 01101111111111111100000000 just like that it's a .txt file — sara, Sep 26 '13 at 11:10

score 0 · Answer 2 · answered Sep 28 '13 at 18:00

Never use eof() as an alternative for checking whether the reading from the file was successful or not.

It could look the following way:

std::ifstream in("test.txt", std::ifstream::in);
if (!in.is_open()) {
    std::cout << "Error opening file";
    return -1;
}

int count0 = 0,
    count1 = 0;
char ch;
while (in.get(ch)) {
    if (ch == '0')
        count0++;
    else if (ch == '1')
        count1++;
}

char and '0' comparison in c++ not giving wanted results

2 Answers2