/in/foo.cc: In function 'int main()':
/in/foo.cc:15:24: warning: iteration 49 invokes undefined behavior [-Waggressive-loop-optimizations]
   printf("%d\n", a[i][0] + a[i][1] + a[i][2] + a[i][3]);
                  ~~~~~~^
/in/foo.cc:10:19: note: within this loop
  for(int i = 0; i <= 49; i++){
                 ~~^~~~~
/in/foo.cc:13:10: warning: iteration 3 invokes undefined behavior [-Waggressive-loop-optimizations]
    printf("%d ", a[i][j]);
    ~~~~~~^~~~~~~~~~~~~~~~
/in/foo.cc:12:20: note: within this loop
   for(int j = 0; j <= 3; j++){
                  ~~^~~~
/in/foo.cc:15:54: warning: array subscript is above array bounds [-Warray-bounds]
   printf("%d\n", a[i][0] + a[i][1] + a[i][2] + a[i][3]);
                                                ~~~~~~^