foo.c: In function 'main':
foo.c:30:26: warning: unused variable 'k' [-Wunused-variable]
   30 |         int i = 0, j = 0,k;
      |                          ^
foo.c:29:29: warning: unused variable 'lb' [-Wunused-variable]
   29 |         int la = strlen(a), lb = strlen(b);
      |                             ^~
foo.c:29:13: warning: unused variable 'la' [-Wunused-variable]
   29 |         int la = strlen(a), lb = strlen(b);
      |             ^~
foo.c:28:50: warning: unused variable 'c' [-Wunused-variable]
   28 |         char a[10000] = { 0 }, b[10000] = { 0 }, c[20000] = {0};
      |                                                  ^

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