Converting an int into a 4 byte char array (C) -

Converting an int into a 4 byte char array (C) -

hey, i'm looking convert int inputed user 4 bytes, assigning character array. how can done?

example:

convert user inputs of 175 to

00000000 00000000 00000000 10101111

issue of answers far, converting 255 should result in 0 0 0 ff although prints out as: 0 0 0 ffffffff

unsigned int value = 255; buffer[0] = (value >> 24) & 0xff; buffer[1] = (value >> 16) & 0xff; buffer[2] = (value >> 8) & 0xff; buffer[3] = value & 0xff; union { unsigned int integer; unsigned char byte[4]; } temp32bitint; temp32bitint.integer = value; buffer[8] = temp32bitint.byte[3]; buffer[9] = temp32bitint.byte[2]; buffer[10] = temp32bitint.byte[1]; buffer[11] = temp32bitint.byte[0];

both result in 0 0 0 ffffffff instead of 0 0 0 ff

just illustration 175 input prints out 0, 0, 0, ffffffaf when should 0, 0, 0, af

the portable way (ensuring 0x00 0x00 0x00 0xaf everywhere) utilize shifts:

unsigned char bytes[4]; unsigned long n = 175; bytes[0] = (n >> 24) & 0xff; bytes[1] = (n >> 16) & 0xff; bytes[2] = (n >> 8) & 0xff; bytes[3] = n & 0xff;

the methods using unions , memcpy() different result on different machines.

the issue having printing rather conversion. presume using char rather unsigned char, , using line print it:

printf("%x %x %x %x\n", bytes[0], bytes[1], bytes[2], bytes[3]);

when types narrower int passed printf, promoted int (or unsigned int, if int cannot hold values of original type). if char signed on platform, 0xff not fit range of type, , beingness set -1 instead (which has representation 0xff on 2s-complement machine).

-1 promoted int, , has representation 0xffffffff int on machine, , see.

your solution either utilize unsigned char, or else cast unsigned char in printf statement:

printf("%x %x %x %x\n", (unsigned char)bytes[0], (unsigned char)bytes[1], (unsigned char)bytes[2], (unsigned char)bytes[3]);

c