View Compilation Error

0_0_21596820_20295.cpp: In function 'int main()':
0_0_21596820_20295.cpp:13:28: error: 'stdout' was not declared in this scope
     freopen("out2.txt","w",stdout);
                            ^
0_0_21596820_20295.cpp:13:34: error: 'freopen' was not declared in this scope
     freopen("out2.txt","w",stdout);
                                  ^
0_0_21596820_20295.cpp:15:20: error: 'maxn' was not declared in this scope
     for(int i=1;i<=maxn;i++)
                    ^
0_0_21596820_20295.cpp:17:9: error: 'cout' was not declared in this scope
         cout<<fun(i,1)+1<<", ";
         ^
0_0_21596820_20295.cpp:17:22: error: 'fun' was not declared in this scope
         cout<<fun(i,1)+1<<", ";
                      ^
0_0_21596820_20295.cpp:18:26: error: 'endl' was not declared in this scope
         if(i%10==0)cout<<endl;
                          ^