problem with character arrays... want to use pointers

Posted on 2004-10-26
Last Modified: 2010-04-15
hi all,

I want to store some large number of characters into a character buffer array... i want to use pointers ..

I am converting some decimal numbers into binary values but now i want to store these binary values into an array which should be of infinite length... i have typecasted the binary values in char...  basically i can store these binary values into arrays of 16  bit length as i need to  sum every 16 bits of the binary values to each of the other 16 bits of binary values i generated.... for example... i have generated binary values of 16 4 13 56.... now i need to store the binary values of these numbers into an array and then split them 16 16 bits and add them...

I hope u got my point....would be very happy if u can help me out..

Question by:somanchivasu
    LVL 5

    Accepted Solution

    i suppose you are trying to do something like this:

    char binary[SOME_BIG_NUMBER];
    int number = (some value);      //this is what you are going to convert
    index i =0;
            binary[i++] = (number % 2) + '0';   // suppose you get zero, you will store 48
            number /= 2;
    binary[i] = 0;

    // you get the binary representation of number in reverse order in binary[] from above. I guess
    it will be fairly easy from here onwards
    LVL 12

    Expert Comment

    Hi somanchivasu,
    The easiest way is to use a fixed-size array, as suggested above. But that's far from elegant, because it can overflow, and if you make it big enough to fit all cases, you're wasting memory for most cases.

    The best compromise is to use a dynamically allocated/reallocated string:

    size_t cur_size=0;
    size_t max_size= 128; /* Arbitrary initialization */
    char* arr = (char*) malloc(max_size);

    When you then insert something into your array, you can test for overflow and realloc accordingly:

    while(cur_size + insert_size >= max_size){
        max_size *= 2;
        arr = (char*) realloc(arr,max_size);

    Now you can insert and it will grow dynamically. Don't forget to update cur_size accordingly.



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