View Compilation Error

555848_0_0_23916.cpp: In function `int searchMaxSubString(char*)':
555848_0_0_23916.cpp:18: error: `strrev' undeclared (first use this function)
555848_0_0_23916.cpp:18: error: (Each undeclared identifier is reported only once for each function it appears in.)
555848_0_0_23916.cpp: At global scope:
555848_0_0_23916.cpp:33: error: `main' must return `int'