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/*
Challenge 120
TASK #1 - Swap Odd/Even bits
Submitted by: Mohammad S Anwar
You are given a positive integer $N less than or equal to 255.
Write a script to swap the odd positioned bit with even positioned bit and
print the decimal equivalent of the new binary representation.
Example
Input: $N = 101
Output: 154
Binary representation of the given number is 01 10 01 01.
The new binary representation after the odd/even swap is 10 01 10 10.
The decimal equivalent of 10011010 is 154.
Input: $N = 18
Output: 33
Binary representation of the given number is 00 01 00 10.
The new binary representation after the odd/even swap is 00 10 00 01.
The decimal equivalent of 100001 is 33.
*/
#include <iostream>
using namespace std;
int swap_bits(int n) {
int out = 0;
int shift = 0;
while (n > 0) {
if ((n & 1) != 0) { out |= 2 << shift; }
if ((n & 2) != 0) { out |= 1 << shift; }
n >>= 2;
shift += 2;
}
return out;
}
int main(int argc, char* argv[]) {
int n = 0;
if (argc == 2) n = atoi(argv[1]);
cout << swap_bits(n) << endl;
}
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