View Compilation Error

0_0_38151872_12062.cpp: In function 'int main()':
0_0_38151872_12062.cpp:5:15: error: 'scanf' was not declared in this scope
  scanf("%d",&m);
               ^
0_0_38151872_12062.cpp:28:24: error: 'abs' was not declared in this scope
    sum=sum+abs(a[i]-mid);
                        ^
0_0_38151872_12062.cpp:30:20: error: 'printf' was not declared in this scope
   printf("%d\n",sum);
                    ^