/in/foo.cc: In function 'int main()':
/in/foo.cc:20:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   20 |    if (a[i] == '{')
      |       ^
/in/foo.cc:26:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   26 |    if (a[i] == '(')
      |       ^
/in/foo.cc:32:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   32 |    if (a[i] == '[')
      |       ^
/in/foo.cc:38:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   38 |    if (a[i] == '<')
      |       ^