one_line_swap.c

// Intro- Strange one-liners that swaps value of two variables.
 
#include <stdio.h>

main(){
    int a=5, b=7;

    a-=b=(a+=b)-b; // Developer- Minhas Kamal (https://minhaskamal.github.io)
                   // Details- https://cloud.githubusercontent.com/assets/5456665/21447433/bc21ad60-c8fe-11e6-9154-b3b682cad607.png
    printf("%d %d\n", a, b);
 
    a=(int[]){b, b=a}[0]; // Expanded- int[] arr = {b, b=a}; a = arr[0];
    printf("%d %d\n", a, b);
    
    a^=b^=a^=b; // Developer- Chris Taylor (http://chris-taylor.github.io/)
                // Details- http://chris-taylor.github.io/blog/2013/02/25/xor-trick/
    printf("%d %d\n", a, b);
    
    a=b+a-(b=a); //Details- http://stackoverflow.com/questions/20800684/why-is-a-ab-b-a-a-bad-choice-for-swapping-two-integers
    printf("%d %d\n", a, b);
 
    // This python code swaps value of two variables- 
    //     a, b = b, a
    // Details- https://stackoverflow.com/questions/21047524/how-does-swapping-of-members-in-the-python-tuples-a-b-b-a-work-internally
 
    // Bonus- Get the max number without using logical operation
    int m = (a+b+((a-b)>>sizeof(int)*8-1|1)*(a-b))/2; // Developer- Minhas Kamal (https://minhaskamal.github.io)
                                                      // Details- https://stackoverflow.com/a/41736445/4684058
                                                      // Another Solution- If both both numbers are positive
                                                      //                   then this works too:
                                                      //                   m = (int[]){a,b}[1-!!(a/b)]
    printf("%d \n", m);
}