foo.cc: In function 'int main()':
foo.cc:16:3: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
   else
   ^~~~
foo.cc:18:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'else'
    if(L1>=L/2)
    ^~