View Compilation Error

0_0_38242037_13942.cpp:1:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
0_0_38242037_13942.cpp:2:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
0_0_38242037_13942.cpp: In function 'int main()':
0_0_38242037_13942.cpp:7:14: error: 'scanf' was not declared in this scope
 scanf("%d",&T);
              ^
0_0_38242037_13942.cpp:10:14: error: 'n' was not declared in this scope
 scanf("%lf",&n);
              ^
0_0_38242037_13942.cpp:11:14: error: 'pow' was not declared in this scope
 b=pow(2.0,n-2)*(n+1);
              ^
0_0_38242037_13942.cpp:12:19: error: 'printf' was not declared in this scope
 printf("%.0lf\n",b);
                   ^