Tom.G said:
yungman said:
yungman said:
Did you read, I said lately. I thank everyone that help me.Vanadium 50 said:
Yes! As they say, "Practice makes perfect."yungman said:
Thanks you for the encouragement. I needed that. Particularly I was tripped up by the algebra question from my little grand daughter. She's only freshman in high school! We Chinese called this the old cat got its whiskers burned.Tom.G said:
Thanks. Why is that so? I know I read from Mark also, but the books keep using it. I know I need to type std::cout <<...; every time if I don't use namespace std. I was wondering why my invItem.h need it. I don't have cin or cout:Jarvis323 said:
#ifndef invItem_H
#define invItem_H
#include <cstring>
#include <string>
using namespace std;
class invItem
{
private:
string* description;
double cost;
int units;
public:
//Constructor. pointer desc points to C-string, c for cost, u for units.
invItem(string** desc, double c, int u)
{
string St2 = **desc;//St2 = St1 in main.
int length = St2.length();
description = new string[length];//allocate new memory using pointer description.
*description = St2;//copy the description to memory
*desc = description;
cost = c; units = u;
}Like I said, it's usually fine in a cpp file, but should be avoided in .h files.yungman said:
Thank you, no wonder I got error lining up on me! I only know cin and cout!Jarvis323 said:
You are missing the point that was discussed about 500 posts ago in a different thread that the ease of use of the Standard Template Library (STL) classes comes with three penalties:yungman said:
Thanks so much for the reply. I did not know that. I don't recall I ever ask this question. I don't even know enough to ask.pbuk said:
These are almost the same, with the only difference being that a C-string is a null-terminated array of type char, and a char array is just an array of type char.yungman said:
The line with "#include <cstring>" should be deleted. The code shown doesn't use any C-strings.yungman said:
There's a big difference between C-strings (i.e., null terminated character arrays) and the standard template library (STL) string template class. C-strings are so called because this is how strings were implemented in C, before C++ came on the scene.yungman said:
When you pass a C-string to a function, what's being passed is a pointer to the first character of the string. If your function is intended to modify a C-string parameter, you'll run into problems if the function tries to insert more characters than the C-string had allocated to it.yungman said:
#include <cstring> // For strcpy_s()
#include <iostream>
using std::cout;
using std::endl;
void modifyStr(char * str);
int main()
{
char Str[10] = "dogs";
cout << "Before modification: " << Str << endl;
modifyStr(Str);
cout << "After modification: " << Str << endl;
}
void modifyStr(char * str)
{
strcpy_s(str, sizeof("hot dogs"), "hot dogs");
}An STD string object will generally take up more space in memory, I believe, because in addition to the memory used to store the characters in the string, there is also memory set aside in reserve, in case you append some more characters to the string.yungman said:
Mark44 said:
We're just talking about a few bytes, say 20 to 30, so it's not like a massive hit on memory.yungman said:
Ah, it's time for me to get more familiar with c-string anyway, what is an extra day or so.Mark44 said:
Yes, good catch. What I was talking about was actually heap fragmentation, but the effect on a microcontroller is much the same.Jarvis323 said:
Ha ha, You ruin my day!pbuk said:
string firstName, lastName;
cout << "Enter your first name: ";
cin >> firstName;
cout << "Enter your last name: ";
cin >> lastName;
string fullName = firstName + " " + lastName;
int one;
one = 2;This cannot be stressed enough.jtbell said:
I deleted the post, I want to check more first.pbuk said:
The time to 'check more first' is before you first post it, not after someone has helped you with it. Goodbye, and good luck.yungman said:
#include <iostream>
#include <iomanip>
#include <string>
#include "invItem.h"
using namespace std;
int main()
{
const int size = 21;
//call default constructor #1
char cAr[size] = "Hammer";
invItem item1;
item1.setDesc(cAr);
item1.setCost(6.95);
item1.setUnits(12);
//call constructor #1 with all parammeters.
cout << left << setw(30) << " Item description: " << item1.getDesc() << "\n";
cout << left << setw(30) << " Cost: " << "$" << item1.getCost() << "\n";
cout << left << setw(30) << " Units on hand: " << item1.getUnits() << "\n\n";
return 0;
}#ifndef invItem_H
#define invItem_H
#include <cstring>
#include <string>class invItem
{
private:
char* description;
int L = 21;//default length.
double cost;
int units;
public:
//Constructor #1 with no parameter
invItem()
{
description = new char[L];
*description = '\0';//First char = NULL
cost = 0.0; units = 0;
}
//Mutator function
void setDesc(char* d) { description = d; }
void setCost(double c) { cost = c; }
void setUnits(int u) { units = u; }
//Accessor functions
const char* getDesc() const { return description; }
double getCost() const { return cost; }
int getUnits() const { return units; }
};
#endifYou did NOT read the content of my post before you made the accusation. You accusation was WRONG. I checked everything carefully. Did you read that I copied the EXACT .h and .cpp into another project and it compiled and ran like a champ? I bet you did not read that.pbuk said: