View Compilation Error

0_0_21805843_13977.cpp: In function 'int change(char*)':
0_0_21805843_13977.cpp:17:24: error: 'strcmp' was not declared in this scope
   if( strcmp(addr[i], s)==0 ){
                        ^
0_0_21805843_13977.cpp:21:21: error: 'strcpy' was not declared in this scope
  strcpy(addr[++m], s);
                     ^
0_0_21805843_13977.cpp: In function 'int main(int, const char**)':
0_0_21805843_13977.cpp:91:21: error: 'strcpy' was not declared in this scope
   strcpy(addr[1], st);
                     ^
0_0_21805843_13977.cpp:94:20: error: 'strcmp' was not declared in this scope
   if( strcmp(st, ed) == 0 ){
                    ^