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I was learning Adam Drozdek's book "Data Structures and Algorithms in C++", well, I typed the code in page 15 in my vim and compiled it in terminal of my Ubuntu 11.10.

#include <iostream>
#include <cstring>
using namespace std;
struct Node{
    char *name;
    int age;
    Node(char *n = "", int a = 0){
        name = new char[strlen(n) + 1];
        strcpy(name, n);
        age = a;
Node node1("Roger", 20), node2(node1);
cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
strcpy(node2.name, "Wendy");
node2.name = 30;
cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
But there's some error:
oo@oo:~$ g++ unproper.cpp -o unproper
unproper.cpp:15:23: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]
unproper.cpp:16:1: error: ‘cout’ does not name a type
unproper.cpp:17:7: error: expected constructor, destructor, or type conversion before ‘(’ token
unproper.cpp:18:1: error: ‘node2’ does not name a type
unproper.cpp:19:1: error: ‘cout’ does not name a type
I have searched this,this,this and this, but I can't find the answer.
Any help would be appreciated:)
                You're missing your main. The code is outside of a function and is considered by the compiler to be either a declaration of variables, class, structs or other such commands. Just put all of the bottom code into int main()
– user1241335
                Mar 29, 2012 at 23:29
The problem is that the code you have that does the printing is outside of any function.  Statements that aren't declarations in C++ need to be inside a function.  For example:
#include <iostream>
#include <cstring>
using namespace std;
struct Node{
    char *name;
    int age;
    Node(char *n = "", int a = 0){
        name = new char[strlen(n) + 1];
        strcpy(name, n);
        age = a;
int main() {
    Node node1("Roger", 20), node2(node1);
    cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
    strcpy(node2.name, "Wendy");
    node2.name = 30;
    cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
                It’s part of a more general rule that only declaration statements can appear outside of functions in C++. I don’t know if there’s a deep philosophical reason for that or whether it’s a historical artifact.
– templatetypedef
                Apr 13, 2021 at 15:29
You are missing the function declaration around your program code. The following should solve your error:
#include <iostream>
#include <cstring>
using namespace std;
struct Node{
    char *name;
    int age;
    Node(char *n = "", int a = 0){
        name = new char[strlen(n) + 1];
        strcpy(name, n);
        age = a;
int main()
    Node node1("Roger", 20), node2(node1);
    cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
    strcpy(node2.name, "Wendy");
    node2.name = 30;
    cout << node1.name << ' ' << node1.age << ' ' << node2.name << ' ' << node2.age;
The error you then get (something like "invalid conversion from int to char*") is because you try to set an integer value (30) to a string attribute (name) with
node2.name=30;
I think
node2.age=30;
would be correct.
If you want to use cout outside the function you can do it by collecting the value returned by cout in boolean.see the below example
#include<iostream>
using namespace std;
bool b=cout<<"1";
int main()
return 0;
output:
error prog.cpp:4:14: error: cannot convert 'std::basic_ostream<char>' to 'bool' in initialization
 bool b=cout<<"1";
for Class Error : you Should Use the cout inside any method of the class.You cannot use cout openly in any class.
class result:public exam{
public:
    display_result()
    float percentage;
    percentage=(physics + maths) / 2;
    get_roll_number();
    getmarks();
    cout << "The Final Percentage of the Student is =" <<percentage<< "%" << endl;
        
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