Last active
August 29, 2015 14:13
-
-
Save scvalex/ec42f4fdfcec7de3e33c to your computer and use it in GitHub Desktop.
Variable Length Arrays in C
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| all: var_len_arrays.c | |
| gcc -O1 var_len_arrays.c -S |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <stdio.h> | |
| void __attribute__ ((noinline)) exercise(int *arr, int n) { | |
| int i; | |
| for (i = 1; i < n; ++i) { | |
| arr[i] = arr[i - 1] ^ arr[i]; | |
| } | |
| } | |
| void foo() { | |
| int arr[10]; | |
| arr[3] = 1234; | |
| exercise(arr, 10); | |
| } | |
| void bar() { | |
| int arr[10]; | |
| int brr[12]; | |
| arr[3] = 1234; | |
| brr[3] = 5678; | |
| exercise(arr, 10); | |
| exercise(brr, 12); | |
| } | |
| void baz(int n) { | |
| int arr[n]; | |
| arr[3] = 1234; | |
| exercise(arr, n); | |
| } | |
| void bam(int n) { | |
| int arr[n]; | |
| int brr[n]; | |
| int crr[n]; | |
| int drr[n]; | |
| int err[n]; | |
| int frr[n]; | |
| int grr[n]; | |
| int hrr[n]; | |
| int irr[n]; | |
| int jrr[n]; | |
| int krr[n]; | |
| int rrr[n]; | |
| arr[3] = 1234; | |
| brr[3] = 1234; | |
| crr[3] = 1234; | |
| drr[3] = 1234; | |
| err[3] = 1234; | |
| frr[3] = 1234; | |
| grr[3] = 1234; | |
| hrr[3] = 1234; | |
| irr[3] = 1234; | |
| jrr[3] = 1234; | |
| krr[3] = 1234; | |
| rrr[3] = 1234; | |
| exercise(arr, n); | |
| exercise(brr, n); | |
| exercise(crr, n); | |
| exercise(drr, n); | |
| exercise(err, n); | |
| exercise(frr, n); | |
| exercise(grr, n); | |
| exercise(hrr, n); | |
| exercise(irr, n); | |
| exercise(jrr, n); | |
| exercise(krr, n); | |
| exercise(rrr, n); | |
| } | |
| int main(int argc, char *argv[]) { | |
| printf("Ok!\n"); | |
| return 0; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Blog post explaining this code: https://scvalex.net/posts/40/