Swap without using a third variable

We know how to swap 2 values using a third temp variable. This is how you do it without using a third variable.

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#include "stdio.h" static void swap(int *x, int *y) { *x = *x + *y; *y = *x - *y; *x = *x - *y; return; } static void swap_xor(int *x, int *y) { *x = *x ^ *y; *y = *x ^ *y; *x = *x ^ *y; return; } int main(int argc, char **argv) { int x = 10, y = 20; printf("1> %d %d\n", x, y); swap(&x, &y); printf("2> %d %d\n", x, y); swap_xor(&x, &y); printf("3> %d %d\n", x, y); return 0; }

[root@Imperfecto_1 ~]# gcc -g run.c && ./a.out
1> 10 20
2> 20 10
3> 10 20