/in/foo.cc: In function 'int main()':
/in/foo.cc:26:4: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
    else;
    ^~~~
/in/foo.cc:27:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
     a[i][j]=n*i-j+1;
     ^