How to print the byte representations of a short int C object

Question

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Print an int in binary representation using C

How would I print the byte representations of a short int, and double in C.

As in lets say I have a function display_shortInt, how would I make it print the byte representation of a short int? I'm new to C, thanks you!

score 7 · Accepted Answer · answered Sep 11 '12 at 22:17

What about this?

void print_bytes(void *p, size_t len)
{
    size_t i;
    printf("(");
    for (i = 0; i < len; ++i)
        printf("%02X", ((unsigned char*)p)[i]);
    printf(")");
}

void print_short(short x)
{
    print_bytes(&x, sizeof(x));
}

void print_double(double x)
{
    print_bytes(&x, sizeof(x));
}
//etc.

That will print the bytes that form the value, in hexadecimal, two characters per byte.

For example, in a little-endian machine, print_short(42) will print (2A00). In a big-endian machine it will be (002A).

score 2 · Answer 2 · answered Sep 11 '12 at 22:14

2

There is no direct way (i.e. using printf or another standard library function) to print it. You will have to write your own function.

void printbits(unsigned int v) {
   for (; v; v >>= 1) 
      putchar('0' + (v & 1));
}

answered Sep 11 '12 at 22:14

Rami Jarrar

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score 2 · Answer 3 · answered Sep 11 '12 at 22:48

2

If you want to see how it is organised in memory (architecture-dependent):

short val = 0x1234;
printf( "%02x%02x", ((char*)&val)[0], ((char*)&val)[1] );

If you just want to see how it is written (big-endian):

printf( "%04x", val );

answered Sep 11 '12 at 22:48

paddy

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1

But note that if `char` is signed (and it is in many architectures), and the byte if greater than 0x80, you will get some funny values. – rodrigo Sep 12 '12 at 07:55

How to print the byte representations of a short int C object

3 Answers3