myClass is a class I have. Now, in the class, I have a function what_value and I need to get the classes.at(0) from the pointer to it in another function. But the problem is, how can I do it? I'm completely stumped, here's what I thought of:
newClass.*myclass.what_value();
And it I get an error from the compiler. Basically, how can I do this in another function with a pointer:
Here is the part of my code that I need to return two values. I am working on a roulette program and I need to return the choice and the number they are betting on. How can I use a pointer to achieve this?
Code: int makeBet(char choice, int num){
printf(" What type of bet would you like to place? "); printf(" Type n for number. Type e for even/odd. Type d for dozen.
I am trying to return a pointer from a method. Below is a sample of my code.
CSubnode * CTest::GetSubNode() { return m_psubnode;//this is declared in CTest as CSunbnode * m_psubnode } //in another class m_subnode = m_ptest->GetSubNode(); //m_subnode is declared as a pointer
I passed the address of the vector to the function. And then display the address. It is a pretty common operation. But it just won't work. But then we do something simple similar to that of the vector. But it works.
I need understanding the logic behind this function. The function is supposed to "Return a pointer to the character at the index given" . For example, what exactly are we declaring at "(char * const c, int index)"? where does "index" come from or equal to in the body of the function?
Code: 1 2 3 4 5 6 7 8
char * GetValueAtIndex(char * const c, int index) { int i = 0; char *p = c; while (i++ != index) p++; return p; }
question from chapter 11, qn 8 modern C programming by king
Write the following function: Code: int *find_largest(int a[], int n); When passed an array a of length n, the function will return a pointer to the array's largest element
Code:
#include <stdio.h> int *find_largest(int a[], int n) { int i, x; x = 0;
[Code].....
have traced the code line by line and it prints correctly up to line 31. However, when the program exits (line 35) , it goes to some other screen with very complex code and my output disappears.
Just to clarify: If I just run the code as is, there is no output. However, when I trace the code line by line, the output appears, but then disappears as the program exits My input was 1 2 3 4 5 6
I'm trying to write a function that returns a pointer to a dynamically allocated array. Here's my code:
#include <iostream> using namespace std; void IndexArray(int, int); int main(){ int *arr, n;
[Code] ....
When I try running the program, I get the error
"Unable to start program 'D:C++FilesdynamicArraySolReleasedynamicArray.exe'. The system cannot find the file specified."
I'm honestly not sure if the issue is my program, or something with C++. At the moment, I cannot debug any of my programs or else I get the same exact error. I basically need to release everything without debugging it. I last used C++ about a year ago and I'm finally back in school, and so trying to get back into it. I use Microsoft Visual C++ 2010.
I know that if I just use "return" by itself the warning goes away but fails to exit when the error occurs. I also believe this may not be the correct use of stderr. But I need the program to exit when an error has occurred.
I am making a function that will return a pointer to a long long variable. For example, I have the next variable prototype: Code: long long funcName(long long x, int s); I want to change the return value, and the first parameter to pointers to long long.
i need to return a struct pointer dynamically allocated inside a function call void function() which is done using 'out parameters' in following code
struct my_struct { int x; } void my_function( my_struct** result ) { my_struct* x = new my_struct{ 10 }; //... *result = x; }
Now i have a doubt, so if i want to print the return value from struct pointer, should i need to print it in the void function() or in the caller the function...
I am writing a class Player which has several char arrays as private fields. I am trying to write a method which returns an array as a pointer, but doesn't alter the array in any way, thus the const.
Here is a snippet:
Code: class Player { private: char state[MAX_STATE_CHAR + ONE_VALUE]; int rating; char last[MAX_NAME_CHAR + ONE_VALUE]; char first[MAX_NAME_CHAR + ONE_VALUE]; int groupNumber = NEG_ONE; public: char * GetFirst() const { return first; }
Visual studio is saying that the return type doesn't match.
The code below is supposed to fill, show, and revalue property. The fill function is supposed to return a pointer that creates a range of property values. The show function is supposed to show the property values entered and the revalued property values. I think part of the problem is the returned pointer from the fill function. Once that is cleared up, I think I will find more problems.
Code:
#include <iostream> const int Max = 5; // function prototypes double fill_array(double ar[], int limit); void show_array(double * begin, double * end);
I'm writing some functions pertaining to binary trees. I've used recursion once before while learning quicksort but am still quite new and unfamiliar with it. And this is my first time touching a binary tree. So my question: In my addnode function, will the return root statement at the end ever return a value other than the value passed to the function?
#include <iostream> using namespace std; int n; int& test();
[Code] ....
Explanation
In program above, the return type of function test() is int&. Hence this function returns by reference. The return statement is return n; but unlike return by value. This statement doesn't return value of n, instead it returns variable n itself.
Then the variable n is assigned to the left side of code test() = 5; and value of n is displayed.
I don't quite understand the bold sentence. Shouldn't value of n and variable n be the same?
I was having problems changing the value of my head node I passed it as an argument as head which would be the address. The parameter was defined as struct node *head. like this
I tried manipultaing pointer values to change head node value but it did not work. I saw some code online which used pointer to pointers(in code below) to change head node value it worked I dont fully understand why. Would like better understanding of why.
Would also like to know why the argument call needed &head instead of just head.
remove = deleteNode(&head,found); opposed to remove = deleteNode(head,found);
I have to write a program to print pascals triangle and stores it in a pointer to a pointer , which I am not entirely sure how to do. I also have to write the file and read it, then create a binary file. Assignment is attached. I am not the best with programming and especially with pointers. I will post my code below.
Code: #include <stdio.h> #include <stdlib.h> void writePascalTriangle(char *fileName, int heightOfTriangle, int **triangle) { FILE *fp; fp=fopen("writePascalTriangle.txt", "w");
I'm making a system like twitter for class called ShoutOut.com I want to be able to get the PublicShoutOut pointer pointed to by the start iterator and assign it to firstShoutOutToDisplay and secondShoutOutToDisplay because I need that in order to pass the pointers to one of my functions. When I step through the debugger the values in start are all default values like "" and so are the values in this->firstShoutOutToDisplay but the message that start points to is being output just fine.
EDIT: got rid of irrelevant code. Am I using the correct syntax to do this?
if (start != finish) { //getting these because a shoutout needs to be passed to the function that displays //options for a shoutout this->firstShoutoutToDisplay = (*start);
const void insertStuff(const void *key, const int value){ // I want to convert the void pointer into one // of three types of pointers(int, string, or double) switch(value){ case 0: int *intPtr = key;
[Code] .....
But this causes an error of: "crosses initialization of int*intPtr"
i have been fiddling with pointers but I don't understand how the proper syntax is written when I want to acces an element of an array through a pointer to a pointer...The code is all mostly just random bs for learning purposes. I marked the problem "// THIS LINE"
This is a sample program that declares a Matrix as a structure with an array as a pointer to a pointer. The following program is supposed to store a matrix in the structure "_Matrix" and later print the matrix just entered but it fails giving me a "segmentation fault". The sample code is given below
Code: #include <stdio.h> #include <stdlib.h> struct _Matrix { int row_size; int col_size; int **mat;
i really don't know why has a error in my code, that pass a pointer of pointer (name of a matrix with 2 dimensions). Here is the source code of a simple example where appears segmentation fault when execute (but compiles normal):
#include <stdio.h> #define LINHAS 3 #define COLUNAS 5 float a[LINHAS][COLUNAS]; void zeros(float **p,float m, float n){ int i,j; for(i=0;i<m;i++)
I need to make a copy of a string that is defined by char *full and copy it into a different pointer defined by char *duplicate. I have written code to do this however it will not work and i cannot figure it out my code is as follows:
char *duplicate = (char *)malloc(strlen(full) + 1); strcpy(duplicate, full); /*Make second version of full*/ char *Ptr = strtok(duplicate, " "); /*Split duplicate up*/
I have a full program written but i know this is where the problem is because i have used printf statements to see where the program fails. I get no errors and it compiles successfully but it hits this point of the program and it just stops and windows automatically shuts down the program.
char *full is pointing to: "To be, or not to be? That is the question: Whether 'tis nobler in the mind to suffer The slings and arrows of outrageous fortune, Or to take arms against a sea of troubles,"
I need to duplicate the string because i need to use strtok but i will need the original string later on so i need an unaltered version.
