View Compilation Error

0_0_11492230_24171.cpp: In function `int main()':
0_0_11492230_24171.cpp:25: error: `vis' undeclared (first use this function)
0_0_11492230_24171.cpp:25: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11492230_24171.cpp:25: error: `tag' undeclared (first use this function)