View Compilation Error

0_0_4850117_1274.cpp: In function `int plus(int)':
0_0_4850117_1274.cpp:14: error: `plus' undeclared (first use this function)
0_0_4850117_1274.cpp:14: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4850117_1274.cpp: In function `void newlink()':
0_0_4850117_1274.cpp:27: error: `plus' undeclared (first use this function)