Trouble while compiling code - strncpy char* and string - c++

Question

I have an issue with a class i have created. When i compiling this so occures error message. Its basically all about char* to string. Here is my class
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
class Stock //klassdekleration
{
private:
char company[30];
int shares;
double share_val;
double total_val;
void set_tot() {total_val = shares * share_val;}
public:
Stock();
Stock(const char * co, int n = 0, double pr = 0.0);
void acquire(const char * co, int n, double pr);
void buy(int num,double price);
void sell(int num, double price);
void update(double price);
void show();
void compare( Stock );
const char * returncompany();
int returnshares();
};
#endif
// class function
//------------------------------------------------------------------------------------------------------
// constructor
Stock::Stock()
{
cout << "pre constructor is called \n";
strcpy(company, "namnlöst");
shares = 0;
share_val = 0;
total_val = 0;
}
Stock::Stock(const char * co, int n, double pr)
{
cout << " Constructor that use " << co << " is called \n";
strcpy("company", co);
company[29] = '\0';
shares = n;
share_val=pr;
set_tot();
}
//---------------------------------------------------------------------------------------------------------
// andra metoddefintioner
void Stock::acquire(const char * co, int n, double pr)
{
strcpy(company, co); //trunkera co om det behövs
company[29]='\0';
if (n<0)
{
cerr << "amount of shares cant be negative "
<< "share put to 0. \n";
shares = 0;
}
else
shares = n;
share_val = pr;
set_tot();
}
void Stock::buy(int num, double price)
{
if (num < 0)
{
cerr << "Amount of bought shares cant be negative. "
<< "transaction cancelled. ";
}
else
{
shares += num;
share_val = price;
set_tot();
}
}
void Stock::sell(int num, double price)
{
if (num < 0)
{
cerr << "amount of sold shares cant be negative. "
<< "Transaction cancelled. ";
}
else if (num > shares)
{
cerr << "cant sell more shares than you posses"
<< "Transaction cancelled. ";
}
else
{
shares -= num;
share_val = price;
set_tot();
}
}
void Stock::update(double price)
{
share_val = price;
set_tot();
}
void Stock::show()
{
cout << "Company: " << company
<< " Shares: " << shares << " \n"
<< " share value: $" << share_val
<< " Total value: $ " << total_val << " \n";
}
int Stock::returnshares()
{
return shares;
}
const char * Stock::returncompany()
{
return company;
}
void Stock::compare(Stock stock2)
{
if (shares < stock2.returnshares())
{
cout << "Company" << stock2.returncompany() << "have higher share value than" << company;
}
else
{
cout << "Company" << company << "have higher share value than" << stock2.returncompany();
}
}
I get this error message.
In constructor ‘Stock::Stock(const char*, int, double)’:
Stock_class.cc:60:23: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
strcpy("company", co);
any idea how i can fix this issue ?
kind regards
Hampus hahne

Answer 1

It seems fairly obvious, you wrote
strcpy("company", co);
when you meant
strcpy(company, co);
Attention to detail is required.
Also
company[29]='\0';
is unnecessary because strcpy always adds a '\0' character, so you don't need to add one as well.

Answer 2

i think in your code strcpy(company,co) will fix you problem.
usage of strcpy was not proper please follow below link for more details:
https://www.geeksforgeeks.org/strcpy-in-c-cpp/