View Compilation Error

0_0_28922679_24465.cpp: In function 'int main()':
0_0_28922679_24465.cpp:17:42: error: 'strcmp' was not declared in this scope
     while(scanf("%s", s), strcmp(s, "END"))
                                          ^
0_0_28922679_24465.cpp:21:9: error: 'x' was not declared in this scope
         x=abs(a);
         ^
0_0_28922679_24465.cpp:22:9: error: 'y' was not declared in this scope
         y=abs(b);
         ^