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#include <stdio.h> cbs () { unsigned int v; /* count the number of bits set in v */ unsigned int c; /* c accumulates the total bits set in v */ printf(“Enter v”); scanf(“%u”,&v); for (c = 0; v ; c++) { v = v & (v – 1); /* clear the least significant bit …
Continue reading “How to write an algorithm to find the number of bits set in a typical number ?”
/* detect if two integers have opposite signs */ #include <stdio.h> int x , y; typedef int bool; bool f; int sdetect(x , y) { f = ((x ^ y) < 0); if ( f == 1 ) { printf(“They have opposite signs\n”); } else { printf(“They have same signs\n”); } }
#include <stdio.h> #include <stdlib.h> #include <postgresql/libpq-fe.h> int main(int argc, char **argv) { const char *conninfo; const char *serverversion; PGconn *conn; const char *paramtext = “server_version”; conninfo = “hostaddr = 127.0.0.1 dbname = test user = earl password = bigshot”; conn = PQconnectdb(conninfo); if ( PQstatus(conn) != CONNECTION_OK ) { printf(“Unable to establish connection: %s”,PQerrorMessage(conn)); return …
#include <stdio.h> #include <stdlib.h> static inline int little_endian() { int endian = 1; return (0 == (*(char *)&endian)); } int main (int argc, char **argv) { printf(“This machine is “); little_endian() ? printf(“little”) : printf(“big”); printf(” endian\n”); exit(0); }
#include <stdio.h> int main() { typedef int bool; bool f; /* conditional flag */ unsigned int m; /* the bit mask */ unsigned int w; /* the word to modify: if (f) w |= m; else w &= ~m; */ printf(“Enter the word to modify “); scanf(“%u”,&w); printf(“Enter the bit mask “); scanf(“%u”,&m); /* w …
Continue reading “How to write a program to modify a word using a bit mask ?”
$gcc counting-bits-set-naive-way-related.c $./a.out Enter v 8474578 Total bits set in v is 11 $./a.out Enter v 1 Total bits set in v is 1 $./a.out Enter v 2 Total bits set in v is 1 $./a.out 3 Enter v a Total bits set in v is 0 $cat counting-bits-set-naive-way-related.c #include <stdio.h> int main() { unsigned …
Continue reading “Hacking the program for counting bits set”
<?php $val = 1; for($count = 0; $count <=10 ; $count++) { echo “count is …” . $count; echo “\n”; echo “val is …” . $val; echo “\n”; $val = $val << 1; } ?>
#include <stdio.h> int main() { int val1 = 4; int val2 = 18; int mask = 1; /* mask <<= 4; */ mask = mask << 4; printf(“mask is %d\n”,mask); if ( val1 & mask ) { printf(“Bit 5 in val1 is set\n”); } if (val2 & mask ) { printf(“Bit 5 in val2 is …
Continue reading “How to find out if nth bit of a number is set to 1?”
/* determining if an integer is a power of 2 */ #include <stdio.h> int main() { unsigned int v; /* we want to see if v is a power of 2 */ typedef int bool; bool f; printf(“enter number”); scanf(“%d”,&v); f = ( v & ( v – 1) ) == 0; printf(“the result is …
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$cat add-p1.c #include <stdio.h> #include <stdlib.h> int add (int a,int b) { return a + b; } int main() { int a,b; a =3; b =4; int ret = add(a,b); printf(“Result: %u\n”,ret); exit(0); } $gcc add-p1.c $./a.out Result: 7 $