C questino breaking down long int

blackzone · 09-07-2004, 10:10 PM

have a long int = 0X0c00a8c0

want to break it down to 4 integer
int1 = 0x0c
int2 = 0x00
int3 = 0xa8
int4 = 0xc0

how do I do it?

CroMagnon · 09-07-2004, 10:44 PM

Here's one way (you're actually splitting it into bytes, not ints...):

long int a = 0x0c00a8c0;
int int1 = (int)(a >> 24);
int int2 = (int)((a >> 16) & 255) ;
int int3 = (int)((a >> 8) & 255 );
int int4 = (int)(a & 255);

I'm sure there's a more direct way to access the bytes through pointers, but it would be less portable (big-endian vs little-endian).

kingtas · 09-09-2004, 12:08 AM

Convert int to string for parsing digits using the itoa command.

#include<stdio.h>
#include<stdlib.h>

void main()
{
int a=123,i;
char b[10];
itoa(a, b, 10);

for(i=0; i<3; i++)
printf("%c", b[i]);
}

//itoa = integer to alpha (defined in stdlib.h)
//first parameter is the number to be parsed
//second is the pointer variable which holds the parsed value
//third parameter is the base of the number which is parsed
//here 123 is considered to be in base 10

phoenix7 · 09-09-2004, 04:58 AM

Hi
You can this fragment of code.

Code:

#include <stdio.h>

int main (void)
{
    long int a = 0X0c00a8c0;
    unsigned char* c = (unsigned char*) (&a);
    int A [4];
    for (int i = 0; i <= 3; i ++)
    {
        A [i] = *c;
        printf ("0X%2X\n", *c);
	c ++;
    }
    return 0;
}

Cheers,
Mohammad

CroMagnon · 09-09-2004, 05:13 AM

Mohammed's method shows exactly what I was talking about - if you run it on an Intel chip, the numbers come out backwards (0xC0 first, then 0xA8, etc), but if you compile and run the same code on (for example) a 68000 chip, it will be the other way around. So if you want to write portable code, don't do that