View Compilation Error

0_0_16394194_10100.cpp:2:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
0_0_16394194_10100.cpp:3:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
0_0_16394194_10100.cpp: In function 'int main()':
0_0_16394194_10100.cpp:8:18: error: 'scanf' was not declared in this scope
     scanf("%d",&T);
                  ^
0_0_16394194_10100.cpp:34:45: error: 'log10' was not declared in this scope
         else r=log10((double)(n+1)/double(n));
                                             ^
0_0_16394194_10100.cpp:35:26: error: 'printf' was not declared in this scope
         printf("%.5f\n",r);
                          ^