View Compilation Error

0_0_19986584_3392.cpp: In function 'void FastIO::PrintInt(int, const char*)':
0_0_19986584_3392.cpp:97:60: error: 'strlen' was not declared in this scope
         if(append) { for(int i = 0 ; i < (int)strlen(append) ; i++) { putchar(append[i]); } }
                                                            ^
0_0_19986584_3392.cpp: In member function 'void Solver::Insert(const char*)':
0_0_19986584_3392.cpp:123:27: error: 'strlen' was not declared in this scope
         int n = strlen(str), now = 0;
                           ^
0_0_19986584_3392.cpp:125:33: error: 'now' was not declared in this scope
             int & next = states[now].nexts[str[i] - 'a'];
                                 ^
0_0_19986584_3392.cpp:129:16: error: 'now' was not declared in this scope
         states[now].cnt++;
                ^
0_0_19986584_3392.cpp: In member function 'int Solver::Match(const char*)':
0_0_19986584_3392.cpp:174:27: error: 'strlen' was not declared in this scope
         int n = strlen(str);
                           ^