View Compilation Error

0_0_11521600_26613.cpp: In function `void init()':
0_0_11521600_26613.cpp:20: error: `add_edge' undeclared (first use this function)
0_0_11521600_26613.cpp:20: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11521600_26613.cpp: In function `void add_edge(int, int, int)':
0_0_11521600_26613.cpp:25: error: `void add_edge(int, int, int)' used prior to declaration