View Compilation Error

0_0_2861726_6421.cpp: In function `void Add()':
0_0_2861726_6421.cpp:32: error: `strrev' undeclared (first use this function)
0_0_2861726_6421.cpp:32: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2861726_6421.cpp: In function `int main()':
0_0_2861726_6421.cpp:41: error: `strrev' undeclared (first use this function)