C++ :: Initializing Array Of Char Pointers Directly
Nov 24, 2014
I'm learning OpenGL using the C API and some of the functions' argument types have proven a bit challenging to me.
One example is the function Code: glShaderSource(GLuint shader, GLsizei count, GLchar const** string, GLint const* length); It resides in foo() which receives a vector "data" from elsewhere Code: void foo(std::vector<std::pair<GLenum, GLchar const*>> const& data); To pass the pair's second element to glShaderSource's third argument, I do the following:
1. Can I initialize a char const** via initialization list, the way I do a char const*?
Code:
// this works
std::vector<std::pair<GLenum, GLchar const*>> const shader_sources = {
{GL_VERTEX_SHADER, "sourcecode"},
{GL_FRAGMENT_SHADER, "sourcecode"}
};
// but is this possible?
What is the difference between initializing pointers to a memory address using the address operator like int *pointer = &x; or initializing it to a value like int *pointer = x; .. in other words how does p and q point to the same memory address in:
const int ARRAY_LEN = 100; int arr [ ARRAY_LEN ]; int *p = arr; int *q = &arr[0];
I am a little confused while comparing char pointers to integer pointers. Here is the problem:
Consider the following statement; char *ptr = "Hello"; char cArr[] = "Hello";
When I do cout << ptr; it prints Hello, same is the case with the statement cout << cArr;
As ptr and cArr are pointers, they should print addresses rather than contents, but if I have an interger array i.e. int iArr[] = {1, 2, 3};
If I cout << iArr; it displays the expected result(i.e. prints address) but pointers to character array while outputting doesn't show the address but shows the contents, Why??
I have a class that defines a window (a popup dialog of sorts), and I want the name of that window to be constant. The only problem is that the name of the popup needs to match the title of the parent window, and I get the name of the parent in the constructor. So how do I go about defining this member variable to be constant and initializing it with a value in the constructor?
I want to do something like this, but I know this isn't allowed:
/* class.h */ class foo { public: foo(*parentWindowPtr);
[Code] .....
I should mention that yes the name of the parent window is const char *, and I would like to keep it this way.
Below code produces run-time segmentation fault (core dumped) when execution reached line 53: delete [] array
Code 1:
#include <cstdlib> #include <iostream> using namespace std; #define QUANTITY 5 class Parent { protected: int ID;
[Code] ....
Output of code 1:
Constructor of A: Instance created with ID=1804289383 Constructor of A: Instance created with ID=846930886 Constructor of A: Instance created with ID=1681692777 Constructor of A: Instance created with ID=1714636915 Constructor of A: Instance created with ID=1957747793 A::showID() -- ID is 1804289383 A::showID() -- ID is 846930886 A::showID() -- ID is 1681692777 A::showID() -- ID is 1714636915 A::showID() -- ID is 1957747793 Try to delete [] array.. Segmentation fault (core dumped)
Question: Why does segmentation fault happen in code 1 above?
I have the following code. According to this the values of pointers p[0] and p[1] remains unchanged since the swap is made to local variables in swap function.Now my doubt is how can I swap the pointers p[0] and p[1] inside the function swap??
I'm new with working with random binary files. I have a class with a char* pointer stored inside of it, I also have a constructor that takes in a string (of any size) from the user. I then simply store this string into the char *. Once the string is stored in the char *. I reinterpret the instance, and I store the information into the random binary file. Everything works.
Question: Random files must know the size of the object that is being stored inside of it, so why when I enter strings of different sizes into the file, it appears to still be working. for example this is an example of the code:
class info { private: char *phrase; public: info(string n ="unknown"){ phrase = new char[n.size()+1];
[Code] ....
My point is, lets just say for example the object ETC, was some long string, this would still work for me. My question is, I don't believe each object is the same size because I allocate memory for the char pointer in the constructor.
Should I not do this just to be safe, and just use a char array instead of a pointer? (Even tho I would have set a pre-defined size for the string) or is something happening in the back to prevent this from not working?
I am making a tictactoe program that requires me to have a 3 by 3 two dimensional array of integers, in which the constructor should initialize the empty board to all zeroes. The program complies, but it keeps outputting garbage values and i'm not entirely sure why, My print function isn't complete yet, since I want to print out the array in a tic tac toe format, but i'm more concerned with why it's printing garbage values, here is my code:
I am going to be using a boolean variable to mark whether or not a specific field has had data entered into it. I figure the best way to do that is to initialize all the elements of the structures to 0. However, with strings and with the nested structure, I'm not sure how to do this.
Want to initialize a local one dimensional array. How can I do the same without a loop?
Found from some links that int iArrayValue[25]={0}; will initialize all the elements to ZERO. Is it? If yes then can we write below code to initialize the elements to a non-ZERO value?
int iArrayValue[25]={4};
Do we have some other way to initialize an array to a non-ZERO value? Memset can initialize the element to ZERO.
In one of my programs I have a 3x3 array of string that I use to display the outcome to rock, paper, scissors, and another 1x3 used for a number guessing game. I have the arrays declared in the header file as follows:
//Games.cpp string rpsOutcome[3][3] { //row 1 { "Both of you picked rock, you tied. Try again", "You picked rock, the computer picked paper, you lose",
[code]....
From what I've read, Im pretty sure thats how your supposed to initialize multidimensional arrays (using the nested braces), but when I build the project, I get the following error:
I am making a tic tac toe program in which they are asking me to have a 3x3 2 dimensional array of integers and have the constructor initialize the empty board to all zeros. They also want me to place a 1 or 2 in each empty board space denoting the place where player 1 or player 2 would move The problem I'm having is, my code initializes the board to all zeros for each element of the array, and prints it out just fine, but I can't figure out how to re-initialize the values in the array to show where each player moves on the board... I was thinking about having a default constructor that has each value set to zero, and then use a setGame function that can change the values on the board to one or two depending on where the player moves....but I don't know if that's possible.....
1. Declare an array that will hold 3000 numbers 2. Initialize this array by assigning a random number to each element in the array 3. Traverse the array, modifying the current contents of each element in the array so that each value now lies between -3000 and 3000 inclusive 4. Traverse the array to compute the average value of all elements
I have never worked with arrays before and am lost!
is supposed to initialize a 4-dimensional std::array a with a[1][2][3][2] = true.
The commented-out line, which is the desired recursion, does not compile for some reason, and the problem third parameter cannot be deduced. So I placed some temporary lines to work in the special case only. Howw to make that recursion work?
I want to use this array as part of my class. I have tried several different angles trying to get it to work but with out success. I have been checking to see if it works by simply using "cout << dayName[3];" It is printing nothing at all. What is the proper way to initialize this array of strings?
First I tried this: const string dayName[] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
I've made a code to check whether or not a save file has been created correctly, but for some reason it always returns this line: readdata[qa]=='1' as true. in which qa is the counter I use in a for loop and readdata is a character array consisting of 50 characters that are either 0, 1 or 2.
this is the entire code:
#include <iostream> #include <fstream> #include <string> using namespace std;
[Code]....
at first is also went wrong at line 22 and also returned that as true, but then I added brackets and it worked.
I am trying to concatenate two words from a file together. ex: "joe" "bob" into "joe bob". I have provided my function(s) below. I am somehow obtaining the terminal readout below. I have initialized my memory (I have to use dynamic, dont suggest fixing that). I have set up my char arrays (I HAVE TO USE CHAR ARRAYS (c-style string) DONT SUGGEST STRINGS) I know this is a weird way to do this, but it is academic. I am currently stuck. My file will read in to my tempfName and templName and will concatenate correctly into my tempName, but I am unable to correctly get into my (*playerPtr).name.
/* this is my terminal readout joe bob <- nothing is put into (*playerPtr).name, why not? joe bob joe bob seg fault*/ /****************************************************************/ //This is here to show my struct/playerInit
Is there any way to read RAM memory directly. For say i want to access memory location 0x0100 to 0x120. How to do that. how to declare the variable, is it unsigned int. what is the type of read values it hex or ascii. how t cast it.
I'm successfully publishing an app to my website by publishing locally and then uploading the files but one of the options offered is to publish straight to the web site but I can't find anywhere to enter a user name and password for my web site. I could also do it with ftp but since the option is offered to publish directly to the web site I'd like to try that method. I'm using the Click Once method.
