appending character array to string c++

Question

I have a character array of 256 characters or char myArray[256] only the first couple actually hold any information

myArray[0] = 'H';
myArray[1] = 'E';
myArray[2] = 'L';
myArray[3] = 'L';
myArray[4] = 'O';
myArray[5] = NULL;
myArray[6] = NULL;
// etc...

I won't necessarily know exactly what is in the array, but I want to copy what is there, minus the null characters, to my buffer string string buffer

I thought the appropriate way to do this would be by doing the following:

buffer.append(myArray);

And the program would stop reading values once it encountered a nul character, but I'm not seeing that behavior. I'm seeing it copy the entirety of the array into my buffer, null characters and all. What would be the correct way to do this?

Edit: Some working code to make it easier

#include <string>
#include <iostream>

using namespace std;

int main()
{
    string buffer;
    char mychararray[256] = {NULL};

    mychararray[0] = 'H';
    mychararray[1] = 'e';
    mychararray[2] = 'l';
    mychararray[3] = 'l';
    mychararray[4] = 'o';

    buffer.append(mychararray);

    cout << buffer << endl;

    return 0;
}

Just realized I wasn't initializing the null properly and my original way works. Sorry to waste yall's time.

Your "working code" is completely different. You're missing the =NULL part. Which is it? — Luchian Grigore
– Luchian Grigore, Commented Nov 26, 2012 at 4:02
@LuchianGrigore, will all values of mychararray after index 4 not be NULL by default (this is an actual question, I'm quite inexperienced at c++)? — username tbd
– username tbd, Commented Nov 26, 2012 at 4:04
@usernametbd no - if you want them to be 0, set them to 0 yourself explicitly, or just do: char mychararray[256] = { 0 }; — Nik Bougalis
– Nik Bougalis, Commented Nov 26, 2012 at 4:04
You're code (up top, with nulls) should work - see cplusplus.com/reference/string/string/append ... How does 'append' know the size of mychararray? — sje397
– sje397, Commented Nov 26, 2012 at 4:04

Luchian Grigore · Accepted Answer · 2012-11-26 04:02:08Z

10

Try with

buffer += myArray;

should do it. append should also work if you null-terminate the array.

answered Nov 26, 2012 at 4:02

Luchian Grigore

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Comments

hinafu · Accepted Answer · 2012-11-26 04:01:46Z

3

This should do the work:

int c;
while(myArray[c] != NULL) {
  buffer.append(1,myArray[c]);
  ++c;
}

Also, you should do something like this: myArray[5] = '\0'

answered Nov 26, 2012 at 4:01

hinafu

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2 Comments

Luchian Grigore Over a year ago

=NULL and ='\0' are equivalent.

hinafu Over a year ago

He didn't initialize the array, that's why he should put that.

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