0_0_17021739_31388.cpp:3:1: error: 'usingnamespace' does not name a type usingnamespace std; ^ 0_0_17021739_31388.cpp: In function 'void Tarjan(int)': 0_0_17021739_31388.cpp:36:23: error: 'elseif' was not declared in this scope }elseif(ins[v]){ ^