/in/foo.cc: In function 'int main()':
/in/foo.cc:19:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < a.length(); i++)
                   ~~^~~~~~~~~~~~
/in/foo.cc:21:4: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
    if (a[i] == '_'&&a[i + 1] == '_'&&a[i + 2] == '_'&&a[i + 3] == '_')
    ^~
/in/foo.cc:23:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
     if (a[i] == '_'&&a[i + 1] == '_'&&a[i + 2] == '_')
     ^~
/in/foo.cc:13:7: warning: unused variable 'cnt' [-Wunused-variable]
   int cnt[5]{ 0 };
       ^~~