View Compilation Error

0_0_16919695_26331.cpp: In function 'int cmp(const void*, const void*)':
0_0_16919695_26331.cpp:8:38: error: 'strcmp' was not declared in this scope
     return strcmp((char *)a,(char *)b);
                                      ^
0_0_16919695_26331.cpp: In function 'int main()':
0_0_16919695_26331.cpp:28:42: error: 'strcmp' was not declared in this scope
             if(strcmp(color[i-1],color[i])==0)
                                          ^