View Compilation Error

0_0_13484763_18700.cpp: In function 'int main()':
0_0_13484763_18700.cpp:7:18: error: 'scanf' was not declared in this scope
     scanf("%d",&t);
                  ^
0_0_13484763_18700.cpp:10:14: error: 'mem' was not declared in this scope
         mem(a);
              ^
0_0_13484763_18700.cpp:13:90: error: 'sqrt' was not declared in this scope
         b[0]=sqrt((a[0]-a[3])*(a[0]-a[3])+(a[1]-a[4])*(a[1]-a[4])+(a[2]-a[5])*(a[2]-a[5]));
                                                                                          ^
0_0_13484763_18700.cpp:19:19: error: 'sort' was not declared in this scope
         sort(b,b+6);
                   ^
0_0_13484763_18700.cpp:21:34: error: 'printf' was not declared in this scope
         printf("Case #%d: ",ans++);
                                  ^