View Compilation Error

197809_0_18455.cpp: In function `void add(char*, char*, char*)':
197809_0_18455.cpp:21: error: `MAX' undeclared (first use this function)
197809_0_18455.cpp:21: error: (Each undeclared identifier is reported only once for each function it appears in.)
197809_0_18455.cpp:24: error: `A' undeclared (first use this function)
197809_0_18455.cpp:24: error: `B' undeclared (first use this function)