View Compilation Error

0_0_18775482_24953.cpp: In function 'int getSuffix(char*)':
0_0_18775482_24953.cpp:59:20: error: 'strlen' was not declared in this scope
  int len = strlen(s), up = 0;
                    ^
0_0_18775482_24953.cpp:62:3: error: 'up' was not declared in this scope
   up = max(up, w[i]);
   ^
0_0_18775482_24953.cpp:65:13: error: 'up' was not declared in this scope
  getSa(len, up + 1);
             ^