int main() {
unsigned short int v = 7; // First 13 MSB == 0; Last 3 LSB == 1 --> 0000000000000111
unsigned short int toggled_bit = (0xffff ^ v) ; // toggled_bit now have a bits pattern --> 1111111111111000
printf("Actual Variable == %u --- toggled bit value %u\n", v, toggled_bit);
}
The shortest answer, isn;t it?
Now a bigger code; write a function
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/errno.h>
unsigned short toggleBits ( unsigned short a_val) {
return (0xffff ^ a_val);
};
int main(int argc, **argv) {
unsigned short int val = 0;
if(argc < 2) exit(1);
val = (unsigned short) atoi(argv[1]);
printf(" val == %u\n" , val);
for(int i = 0; i < 4; i++) {
val = toggleBits(val);
printf(" val == %u\n" , val);
}
return 0;
}
However, if you wana just toggle a single bit (say n'th bit) , then instead of FFFF, use a value equivalent to 2^n (2 to the power n) and do the XOR operation exactly similar to the above code.
Let me know, if you need any specific question. You still need to explore yourself a lot by writing simple codes doing such bitwise operation to get more clarity.
Last edited by Praveen_218; 06-22-2010 at 02:05 PM..
Reason: Typo mistake corrections and some minor additions ...
This User Gave Thanks to Praveen_218 For This Post:
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LEARN ABOUT CENTOS
systemd-vconsole-setup.service
SYSTEMD-VCONSOLE-SETUP.SERVICE(8) systemd-vconsole-setup.service SYSTEMD-VCONSOLE-SETUP.SERVICE(8)NAME
systemd-vconsole-setup.service, systemd-vconsole-setup - Configure the virtual console at boot
SYNOPSIS
systemd-vconsole-setup.service
/usr/lib/systemd/systemd-vconsole-setup
DESCRIPTION
systemd-vconsole-setup.service is an early-boot service that configures the virtual console font and console keymap. Internally it calls
loadkeys(1) and setfont(8).
See vconsole.conf(5) for information about the configuration files understood by this service.
KERNEL COMMAND LINE
A few configuration parameters from vconsole.conf may be overridden on the kernel command line:
vconsole.keymap=, vconsole.keymap.toggle=
Overrides the key mapping table for the keyboard and the second toggle keymap.
vconsole.font=, vconsole.font.map=, vconsole.font.unimap=
Configures the console font, the console map, and the unicode font map.
See vconsole.conf(5) for information about these settings.
SEE ALSO systemd(1), vconsole.conf(5), loadkeys(1), setfont(8), systemd-localed.service(8)systemd 208SYSTEMD-VCONSOLE-SETUP.SERVICE(8)
06-22-2010
