CareerCup

The only thing I can come up with is reversing bit by bit. I don't think there's any good binary operation for this.

unsigned int a = 100; //just treat a as your binary number, 
unsigned int b = 0; // the final result
int s = sizeof(a) * CHAR_BIT; // # of bits in a;

for(int i = 0; i < s; i++)
{
	b <<=1; // left shift b
	b |= a & 0x1; //get unit bit
	a >>= 1; // right shift a
}
//now b is your result

The logic behind this is:

Let's say
a=1010

Step 1:
a=0101
b=0001
Step 2:
a=0010
b=0010
etc.

google for bit twiddling hacks.

int main()
{
        int x = 0x000000F0;

        x = ((x&0xAAAAAAAA) >> 1)| ((x& 0x55555555)<<1);
        x = ((x&0xCCCCCCCC) >> 2)| ((x& 0x33333333)<<2);
        x = ((x&0xF0F0F0F0) >> 4) | ((x& 0x0F0F0F0F)<<4);
        x = ((x&0xFF00FF00) >> 8) | ((x& 0x00FF00FF)<<8);
        x = x >> 16 | x<< 16;
        printf("%x\n", x);
}

#include <stdio.h>

int reverse_bits(int n){
  return n^(~0);
}

void print_bits(int x) {
  int wl = sizeof(int)*2-1;
  unsigned mask;
  for (mask = 1<<wl; mask; mask >>= 1)
    putchar(x&mask ? '1' : '0');
  putchar('\n');
}

int main(){
  
  int n = 361;
  print_bits(n);

  n = reverse_bits(361);
  print_bits(n);

  return 0;
}

#include "stdio.h"
main()
{
int a,b=0;
int temp=1;
printf("Enter a");
scanf("%d",&a);
while (a>0)
{
b|=(a&temp);
a=a>>1;
if (a)
b=b<<1;
}
printf("reversed number is %d",b);
}

#include<stdio.h>
#include<stdlib.h>
#define size(arr) sizeof(arr)/sizeof(arr[0])
int main(){
        int arr[]               = {1,0,0,0,1,0,1,1,1,0,1,1,0,1,0,0,1}, index=0,index_1=0;
        int num_of_elems        = size(arr);
        int *result             =malloc(num_of_elems*sizeof(int));
        printf("Input : ");
        for(;index <num_of_elems;index++){
                printf("%d ", arr[index]);
                if(1 == arr[index] )
                        result[num_of_elems-index-1]    = arr[index];
        }
        printf("\nOutput : ");
        for (index=0;index<num_of_elems;index++)
                printf("%d ", result[index]);
        printf("\n");
        return 0;
}

void main()
{
    int i=0,temp=1,a=0;
    int x;
    scanf("%d",&x);
    
i=0;
while(i<16)
{
if(x&temp)
{
   a=a|1;
   a=a<<1;
}
else
{
  a=a<<1;
}
x=x>>1 ;
i++ ;
}
printf("%d",a);
}

//This in my opinion is best solution as I love CODING...
reverseBinary(int num){
int rev = 0;
//Considering num is 4 bytes
for(int i=0;i<4*8;i++){
rev = (rev<<1) | (num&1);
num = num>>1;
}
return rev;
}

do
{
if(x&1)
{
printf("1");
}
else
{
printf("0");
}
while(x>>=1);
}

#include<iostream>
using namespace std;
int main()
{
int a,i,j,ar[10000001];
cin>>a;
for(i=0;i<a;i++)
{
cin>>ar[i];
}
for(j=0;j<a;j++)
{
int b=1;
int temp=1;

while (ar[j]>0)
{
b|=((ar[j])&temp);
ar[j]=(ar[j])>>1;
if (ar[j])
b=b<<1;
}
cout<<b<<endl;
}
return 0;
}


Why the above code show mw runtime error , could anyone help me please
thanks...

#include <stdio.h>
unsigned char swapBits(unsigned char n, unsigned char p1, unsigned char p2)
{
return (((n >> p1) & 1) == ((n >> p2) & 1) ? n : ((n ^ (1 << p2)) ^ (1 << p1)));
}

int main()
{
unsigned char n = 2; //any given binary number
unsigned char p1 = 0; //First bit position
unsigned char p2 = sizeof(n) * 8 - 1;//last bit position
while (p1++ < p2--)
{
n = swapBits(n, p1, p2);
}
printf("%d", n);
return 0;

}

Note : This can be done using recursion in shorter way, Try it!

#include <stdio.h>
unsigned char swapBits(unsigned char n, unsigned char p1, unsigned char p2)
{
    return (((n >> p1) & 1) == ((n >> p2) & 1) ? n : ((n ^ (1 << p2)) ^ (1 << p1)));
}

int main()
{
unsigned char n = 2; //any given binary number
unsigned char p1 = 0; //First bit position
unsigned char p2 = sizeof(n) * 8 - 1;//last bit position
while (p1++ < p2--)
{
  n = swapBits(n, p1, p2);
}
printf("%d", n);
return 0;

}

This can be done using recursion in shorter way! try out.

100001101010100101010100111000000011000000111001

#include <stdio.h>
unsigned char swapBits(unsigned char n, unsigned char p1, unsigned char p2)
{
return (((n >> p1) & 1) == ((n >> p2) & 1) ? n : ((n ^ (1 << p2)) ^ (1 << p1)));
}

int main()
{
unsigned char n = 2; //any given binary number
unsigned char p1 = 0; //First bit position
unsigned char p2 = sizeof(n) * 8 - 1;//last bit position
while (p1++ < p2--)
{
n = swapBits(n, p1, p2);
}
printf("%d", n);
return 0;

}

Dont know how exactly you want it in c but i think that you have to do the following operation.

number = number xor 11111111