View Compilation Error

0_0_8318419_29655.cpp: In function `int scs(int, int)':
0_0_8318419_29655.cpp:15: error: `strlen' undeclared (first use this function)
0_0_8318419_29655.cpp:15: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8318419_29655.cpp: In function `void solve_case()':
0_0_8318419_29655.cpp:30: error: `strlen' undeclared (first use this function)