View Compilation Error

0_0_21738841_7143.cpp: In function 'void R(ll&)':
0_0_21738841_7143.cpp:16:30: error: 'getchar' was not declared in this scope
   int f=1;x=0;char c=getchar();
                              ^
0_0_21738841_7143.cpp: In function 'int main()':
0_0_21738841_7143.cpp:63:22: error: 'scanf' was not declared in this scope
   int T;scanf("%d",&T);while(T--){
                      ^
0_0_21738841_7143.cpp:67:7: error: 'cout' was not declared in this scope
       cout<<sum(n)<<endl;
       ^
0_0_21738841_7143.cpp:67:21: error: 'endl' was not declared in this scope
       cout<<sum(n)<<endl;
                     ^
0_0_21738841_7143.cpp:70:5: error: 'cout' was not declared in this scope
     cout<<solve(n,k)<<endl;
     ^
0_0_21738841_7143.cpp:70:23: error: 'endl' was not declared in this scope
     cout<<solve(n,k)<<endl;
                       ^