View Compilation Error

0_0_26533182_5284.cpp: In member function 'bool Compare::operator()(const char*, const char*) const':
0_0_26533182_5284.cpp:15:29: error: 'strcmp' was not declared in this scope
         { return strcmp(s, t)<0; }
                             ^
0_0_26533182_5284.cpp: In function 'int main()':
0_0_26533182_5284.cpp:35:35: error: 'strcpy' was not declared in this scope
                 strcpy(s, &line[0]); strcpy(t, &line[i+2]);
                                   ^
0_0_26533182_5284.cpp:57:43: error: 'strlen' was not declared in this scope
                                 s[strlen(s)-1]=0;
                                           ^