# Xor Party Tricks

> Source: <https://gist.github.com/rexim/6f2349b548fdead7ed790d1a40915ae1>
> Published: 2025-12-07 20:16:27+00:00

dup.c

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#include <stdio.h>

#include <stdlib.h>

#include <time.h>

int xs[] = {7,62,2,46,73,43,26,82,5,95,57,56,44,21,40,79,13,6,9,8,72,59,65,81,60,78,13,85,87,58,48,25,32,47,67,4,31,19,33,1,92,14,53,89,84,54,29,10,17,3,77,70,45,97,34,23,86,55,15,64,68,83,76,41,18,39,94,22,74,11,69,49,12,35,20,90,100,98,36,63,91,38,66,93,50,96,61,71,75,37,52,88,30,28,99,27,42,51,80,24,16};

int main()

{

    int x = 0;

    for (int i = 1; i <= 100; ++i) {

        x ^= i;

    }

    size_t n = sizeof(xs)/sizeof(xs[0]);

    for (int i = 0; i < n; ++i) {

        x ^= xs[i];

    }

    printf("%d\n", x);

    return 0;

}

encrypt.py

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def
 
encrypt
(
m
, 
k
):

 
return
 
''
.
join
([
chr
(
ord
(
a
)
^
k
) 
for
 
a
 
in
 
m
])

ll.c

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#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdint.h>

#include <string.h>

typedef struct {

    int value;

    uintptr_t xored;

} Node;

Node *node_create(int value)

{

    Node *node = malloc(sizeof(*node));

    memset(node, 0, sizeof(*node));

    node->value = value;

    return node;

}

typedef struct {

    Node *begin;

    Node *end;

} Linked_List;

void ll_append(Linked_List *ll, int value)

{

    if (ll->end == NULL) {

        assert(ll->begin == NULL);

        ll->end = node_create(value);

        ll->begin = ll->end;

    } else {

        Node *node = node_create(value);

        node->xored     = (uintptr_t)ll->end;

        ll->end->xored ^= (uintptr_t)node;

        ll->end         = node;

    }

}

Node *node_next(Node *node, uintptr_t *prev)

{

    Node *next = (Node*)(node->xored^(*prev));

    *prev = (uintptr_t)node;

    return next;

}

int main()

{

    Linked_List xs = {0};

    for (int x = 5; x <= 10; ++x) {

        ll_append(&xs, x);

    }

    uintptr_t prev = 0;

    for(Node *iter = xs.end; iter; iter = node_next(iter, &prev)) {

        printf("%d\n", iter->value);

    }

    return 0;

}

swap.c

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#include
 
<stdio.h>

int
 
main
()

{

 
int
 
a
 
=
 
69
;

 
int
 
b
 
=
 
420
;

 
printf
(
"%d %d\n"
, 
a
, 
b
);

 
a
 ^= 
b
; 
// a = 69^420, b = 420

 
b
 ^= 
a
; 
// a = 69^420, b = 69

 
a
 ^= 
b
; 
// a = 420, b = 69

 
printf
(
"%d %d\n"
, 
a
, 
b
);

 
return
 
0
;

}