Problem in printing characters by using class

Hi to all,
Hope you all will be fine. I am new to C++. Although i have read the basics but i am a newbie to C++.
Now i want to learn how to use class in C++. For this i made a simple class, assign variables and simply try to assign values to variables. But i got errors

I wrote very simple code

Code:

---

class Test {
public:
    Test(char* firstNamePointer, char lastName[]);
    Test(const Test& orig);
    virtual ~Test();

    int item;
    char *firstNamePointer;
    char lastName[10];
 
  // string middleName;

private:

};

Test::Test(char* firstNamePointer, char lastName[]) {

    this->firstNamePointer = firstNamePointer;
    this->lastName = "Mahmood";
    //this->lastName = lastName;
}

Test::Test(const Test& orig) {
}

Test::~Test() {
}

int main(int argc, char** argv) {

    Test *test = new Test("Basit", "Mahmood");
    test->item = 5;
 
    //test->middleName = "Ahmed"

    cout << (*test).item << endl;      //ok
    cout << test->item << endl;        //ok

    cout << endl;
    cout << (*test).firstNamePointer << endl;      //ok
    cout << test->firstNamePointer << endl;        //ok

    cout << endl;
    cout << (*test).lastName << endl;
    cout << test->lastName << endl;

    return (EXIT_SUCCESS);
}

---

Error that i got in the case

Code:

---

Test::Test(char* firstNamePointer, char lastName[]) {

    this->firstNamePointer = firstNamePointer;
    this->lastName = "Mahmood";                        //error
}

---

is

Quote:

---

Test.cpp:13: error: incompatible types in assignment of `const char[8]' to `char[10]'

---

and when i use this code

Code:

---

Test::Test(char* firstNamePointer, char lastName[]) {

    this->firstNamePointer = firstNamePointer;
    this->lastName = lastName;                            //error
}

---

then the error is

Quote:

---

Test.cpp:14: error: incompatible types in assignment of `char*' to `char[10]'

---

Also when i try to use string in my code like this

Code:

---

#include <string.h>  //also try <string> and <strings.h>

class Test {
public:
    Test(char* firstNamePointer, char lastName[]);
    Test(const Test& orig);
    virtual ~Test();

    int item;
    char *firstNamePointer;
    char lastName[10];
  // char lastName[10] = "Ahmed";
    string middleName;                        //Unable to resolve identifier string

private:

};

---

why it saying unresolved identifier string even i am including file <string.h>.
How can i use string in my class.

Please tell what i am doing wrong

thanks

The problem is that you cannot assign to an array. You are heading towards a correct solution, i.e., to use std::string, but you need to #include <string> and qualify string as std::string.

I would suggest you go with the string for all "strings".

use #include <string> //string.h isn't a C++ header.

then use std::string (string is part of the std namespace)

std::string middleName ;

Hmm, thanks. The string problem is solved now:). But i want to ask something

I think in the code

Code:

---

Test::Test(char* firstNamePointer, char lastName[], string middleName) {

    this->firstNamePointer = firstNamePointer;
  // this->lastName = "Mahmood";
  // this->lastName = lastName;                  //name = testArray;
    this->middleName = middleName;
}

---

I am trying to do something like this

Code:

---

int main(int argc, char** argv) {
   
    char name[10];
 
    char testArray[20] = "Masood";

    name = testArray;    // this is what i am actually doing in my class( // this->lastName = lastName;)  error
   
    cout << name << endl;

    //char lastName[10] = "Masood";

    // cout << lastName << endl;
}

---

Is it?

But when i change line like this

Code:

---

name[0] = testArray[0];

---

then i got output like this

Code:

---

M[]"a/    //[] is not actually brackets it's something unknown

---

I want to ask the output should be simple "M". what is this ([]"a/)

second i want to ask why this statement is not working. I simply trying to assign value to public member field

Code:

---

  test->item = 5;                    //ok
 
  test->lastName = "Masood";    //error why

---

i think this is same as

Code:

---

char lastName[10] = "Masood";

---

is test->lastName = "Masood"; can be interpreted something like this when i declared lastName variable in a class?

Code:

---


char * const lastName[10]

---

that's why i am getting error like this

Code:

---

main.cpp:24: error: incompatible types in assignment of `const char[7]' to `char[10]'

---

Thanks

this is working

[code]
test->lastName[0] = 'M';
test->lastName[1] = 'a';
test->lastName[2] = 's';
test->lastName[3] = 'o';
/[code]

I already told you that you cannot assign to an array ;)

Hmm now i understood :). Actually i was confused about the working of code. I was mixing these code:)

Code:

---

  char lastName[] = {'M', 'a', 's', 'o', 'o', 'd'};  //same as  char firstName[] = "Masood";

  char firstName[] = "Masood";

  char middleName[10];

  middleName = "Masood";  // main.cpp:38: error: incompatible types in assignment of `const char[7]' to `char[10]'

---

And after understanding this, i came up with this and it's working very well.

Code:

---

#ifndef _TEST_H
#define        _TEST_H

#include <string>

using namespace std;

class Test {
public:
    Test(char* firstNamePointer, char lastName[], string middleName);
    Test(const Test& orig);
    virtual ~Test();

    int item;
    char *firstNamePointer;
    char lastName[10] ;
    string middleName;

private:

};

#endif        /* _TEST_H */

#include "Test.h"

Test::Test(char* firstNamePointer, char lastName[], string middleName) {

    this->firstNamePointer = firstNamePointer;
    strcpy(this->lastName, lastName);
    this->middleName = middleName;
}

Test::Test(const Test& orig) {
}

Test::~Test() {
}

#include <stdlib.h>
#include <iostream>

#include "Test.h"

int main(int argc, char** argv) {

    Test *test = new Test("Basit", "Ahmed", "Mahmood");

    test->item = 5;                    //ok
    //test->middleName = "Kashif";      //ok
  // strcpy(test->lastName, "Masood"); //ok

  // test->lastName[0]= 'M';          //ok
  // test->lastName[1]= 'a';          //ok

    cout << (*test).item << endl;
    cout << test->item << endl;
    cout << endl;

    cout << (*test).firstNamePointer << endl;
    cout << test->firstNamePointer << endl;
    cout << endl;

    cout << (*test).middleName << endl;
    cout << test->middleName << endl;
    cout << endl;

    cout << (*test).lastName << endl;
    cout << test->lastName << endl;
    cout << endl;

    return (EXIT_SUCCESS);
}

---

Thanks :)

Quote:

---

Originally Posted by Basit781

Hmm now i understood :). Actually i was confused about the working of code. I was mixing these code:)

---

Why are you using char* for string data at all?

Your program is easily broken if I give it a last name that is more than 10 characters.

Code:

---

    int item;
    char *firstNamePointer;
    char lastName[10] ;
    string middleName;

---

Get rid of the char* and use std::string for all string data.

Code:

---

Test test("Basit", "ThisisaLongLastName", "Mahmood");

---

This will fail with your code.

Secondly:

Code:

---

Test *test = new Test("Basit", "Ahmed", "Mahmood");

    test->item = 5;                    //ok

---

Why are you using "new" here? This is an indication you don't know how to properly instantiate objects, and not just an oversight.

Code:

---

Test test("Basit", "Ahmed", "Mahmood");

---

Then you don't need "new".

Code:

---

And after understanding this, i came up with this and it's working very well.

---

It doesn't work. I showed you how it is easily broken with a last name of more than 10 characters.

When you write a C++ application, you attempt to make it as bug-free as possible. To do this, you use the safest constructs, one being the use of string classes, not 'C' char* handling as you've done.

Regards,

Paul McKenzie

Quote:

---

Originally Posted by Basit781

Code:

---

  char lastName[] = {'M', 'a', 's', 'o', 'o', 'd'};  //same as  char firstName[] = "Masood";

---

---

Wrong.

Code:

---

  char lastName[] = {'M', 'a', 's', 'o', 'o', 'd', '\0'};  //same as  char firstName[] = "Masood";

---

"" is automatically null-terminated. Not the case with arrays. Don't forget to null terminate your character strings.

Hi :)
Mr. Paul i read your comments and i am very thankful to you for giving me suggestions. I greatly appreciate your suggestions:). But as i already told that i am newbie so it was just an exercise.

Quote:

---

Why are you using char* for string data at all?

Your program is easily broken if I give it a last name that is more than 10 characters.

---

I know it, but i want to see how you can assign value to character array when you use class. I also used string when i was trying this code, you can see in my first post

Quote:

---

Why are you using "new" here? This is an indication you don't know how to properly instantiate objects, and not just an oversight.

---

Actually when i first tried this code then i didn't use new, instead i used the syntax, you suggested

Code:

---

Test test("Basit", "Ahmed", "Mahmood");

test.item = 5;
strcpy(test.lastName, "Masood);
....

---

But i am reading a book in which i encountered advance Pointers topic. In this topic the author used linked list and Tree structures. Although i didn't read the whole topic but i saw the new syntax.
So i tried it with new syntax just like that. I want to see how you can access variables when you used simple construction and when you use new (difference between . and ->) . You can see i used two syntax for printing data

Code:

---

    cout << (*test).firstNamePointer << endl;
    cout << test->firstNamePointer << endl;
    cout << endl;

---

i used it for my understanding.The whole thing was just an exercise. And once you tole me:) that whenever you have some problem just write simple code and then ask:)
But thank you very much for giving me good C++ programming suggestions:)

Thanks monarch_dodra for correcting me about character array null terminator :)

Thanks;)