Converting Ascii to binary in C

Question

So here is my code

void ascToBinary(int character, int *ones)
{
    if(character == 1)
    {
       printf("1");
       *ones+=1;
       return;
    }
    else
    {
        if((character%2) == 0)
        {
             printf("0");
             character = character/2;
        }
        else
        {
             printf("1");
             character = character/2;
             *ones+=1;

        }
        binaryPrinter(character, ones);
    }
}

Can anyone try to help me out on where something is wrong here. It compiles fine and does some ascii letters correct. If you try an 'e' though it will print out '1010011' instead of the correct binary.

All help appreciated Thanks Guys.

If it is not clear here i am trying to convert an inputed character to binary. This is the only way i am aloud to do it through a recursive function and it must be void with those parameters. — 3kings, Feb 23 '14 at 05:46

score 5 · Accepted Answer · answered Feb 23 '14 at 05:48

You print the results in the wrong order. The correct output is '1100101'. You can flip it like this:

    void ascToBinary(int character, int *ones)
    {
        if(character == 1)
        {
           printf("1");
           *ones+=1;
           return;
        }
        else
        {
            char out;
            if((character%2) == 0)
            {
                 out = '0';
                 character = character/2;
            }
            else
            {
                 out = '1';
                 character = character/2;
                 *ones+=1;

            }
            ascToBinary(character, ones);
            putchar (out);
        }
    }

I feel dumb now :( Haha thanks i will accept your answer in a few — 3kings, Feb 23 '14 at 05:54

score 1 · Answer 2 · answered Feb 23 '14 at 05:48

1

You're printing the bits of the character in reverse, since you start printing with the least significant bit.

Therefore the expected value for your function, when called on e is 1010011 which is exactly what you get.

answered Feb 23 '14 at 05:48

Paul

139,544
27
275
264

score 1 · Answer 3 · edited Sep 02 '16 at 18:58

Converting an Integer to binary:

Version 1 - Will print out the binary result

void to_bin(int value)
{
    char base_range[] = "01";

    if (value >= 2) {
        to_bin(value / 2);
    }

    printf("%c", base_range[value % 2]);
}

Version 2 - Will return a string with binary result

void to_bin_str(int value, char *res, int *p)
{
    char base_range[] = "01";

    if (value >= 2) {
        to_bin_str(value / 2, res, p);
    }

    res[(*p)++] = base_range[value % 2];
}

char* convert(int value)
{
    char* result = (char*)malloc(sizeof(char) * 32);
    int i = 0;

    to_bin_str(value, result, &i);
    result[i] = '\0';

    return (result);
}

Version 3 - Will convert to any base from 2 to 16, handles negatives for base 10

void to_base(int value, int base, char *res, int *p)
{
    char base_range[] = "0123456789ABCDEF";

    if (value >= base || value <= -base) {
        to_base(value / base, base, res, p);
    }

    res[(*p)++] = base_range[abs(value % base)];
}

char* convert(int value, int base)
{
    char *result = (char*)malloc(sizeof(char) * 32);
    int i = 0;

    if (base < 2 || base > 16)
        return (NULL);

    if (base == 10 && value < 0)
        result[i++] = '-';

    to_base(value, base, result, &i);
    result[i] = '\0';

    return (result);
}

Converting Ascii to binary in C

3 Answers3

Linked