View Compilation Error

0_0_29468859_28344.cpp: In function 'int main()':
0_0_29468859_28344.cpp:41:38: error: 'scanf' was not declared in this scope
         while(scanf("%d%d%d",&n,&k,&m)!=EOF)
                                      ^
0_0_29468859_28344.cpp:41:41: error: 'EOF' was not declared in this scope
         while(scanf("%d%d%d",&n,&k,&m)!=EOF)
                                         ^
0_0_29468859_28344.cpp:44:37: error: 'memset' was not declared in this scope
             memset(num,0,sizeof(num));
                                     ^
0_0_29468859_28344.cpp:48:33: error: 'sort' was not declared in this scope
             sort(po+1,po+m+1,cmp);
                                 ^
0_0_29468859_28344.cpp:63:34: error: 'max' was not declared in this scope
                 ans=max(ans,fx-fy);
                                  ^
0_0_29468859_28344.cpp:65:32: error: 'printf' was not declared in this scope
             printf("%lld\n",ans);
                                ^