Char passing in C++ with pointers

Question

Im having unclear image of pointers and char passing with functions. please anyone can tell me where im doing wrong and brief idea about pointers?ex : where should i use them, etc...

#include <iostream>
using namespace std;
class book{
private:
    char *CName;
    int CFee;
    int NoPeople;
    int Income;
public:
    void setData(char &x,int y,int z){
        CName = &x;
        CFee = y;
        NoPeople = z;

    }
    void calIncome(){
        Income = CFee * NoPeople;

    }
    void viewIncome(){
        cout<<Income;
        cout<<CName;

    }
};
int main(){
    book b1;
    b1.setData('DISE',20000,30);
    b1.calIncome();
    b1.viewIncome();
}

im getting error in this code

//b1.setData('DISE',20000,30); "non-const lvalue reference to type 'char' cannot bind to a temparory of type 'int'"

Answer 1

In your code there is no need for pointers. You should use std::string :

#include <string>
...
string CName
...
void setData(const string& x,int y,int z){
  CName = x;

and in setData call you should use double quotes (which are for strings) instead of single quotes (which are for individual characters).

Answer 2

b1.setData('DISE',20000,30);

char is only one char, like 'D' , if you have multiple char, that is string, and you need to pass it as "DISE"

With your method signature, void setData(char &x,int y,int z) you can only pass char. That is one character.

Answer 3

You should change setData() declaration to void setData(const char *x,int y,int z)

As you're currently doing you are expecting a reference to a single char as parameter, which cannot be used to assign a char* pointer that is meant to point at a character array.

Also you aren't specifying a character array literal in the call:

b1.setData('DISE',20000,30);

Needs to be changed to

b1.setData("DISE",20000,30);
        // ^    ^

Answer 4

setData metod is completely useless here. Its work should be done by a constructor, and the name variable (which should NOT be named CName should be an std::string . viewIncome should automatically call calIncome and a dirty flag should probably be introduced. Otherwise calIncome should be a free/static function and the income member should be removed. The function parameters should also be reasonably captioned.

And I'll even answer the question:

class Book {
    std::string name;
    int fee;
    int noPeople;
    int income;

public:
    Book(std::string name, int fee, int noPeople) :
        name(std::move(name)),
        fee(fee),
        noPeople(noPeople)
    {
    }

    void calIncome() {
        income = fee * noPeople;
    }

    void viewIncome() {
        calIncome();
        std:: cout << income << name;
    }
};

int main() {
    Book b1 ("DISE", 20000, 30);
    b1.viewIncome();
}

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