this question would their be a different process if they asked "declare and initialize a pointer to the variable int cost[N][N]" Here's what I have so far
[#include<stdio.h>
int main() {
int a; // Step 1
int *ptr; // Step 2
a = cost; // Step 3
ptr = &a; // Step 4
return(0);
[Code] .....
I need to initialize a pointer variable with a knowing address. See code below, ptr is the final destination and value of ptr_address contains the address value, so I need to do something like ptr = *ptr_address.
Code:
int *ptr;
int *ptr_address;
int address;
address = 0x10000005;
ptr_address = &(address);
ptr = *ptr_address;
The problem is that compiler gives the following warning message:
warning: assignment makes pointer from integer without a cast [enabled by default]
Is my code wrong or there is any other way to do it without receiving this compiler warning?
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;
[Code] ......
I remember that the syntax exists I just don't remember what it is.I want to write a conditional function () prior to main (). in that function I'm using a variable that isn't introduced until main (). How do I let C know that I will be int'ng this function prior to the point where it is going to be accessed so that it doesn't freak out? alternatively is it possible to int the variable in both main() and my conditional function so that it exists? I imagine this would cause an issue because I would essentially be int'ng it twice.
I've done the cursory google searches however I don't think I'm using the correct keywords to get the results I'm looking for. If necessary I would be more than happy to post the code it's just a simple 40 line homework assignment.
How to declare variable for all void() as I have another void s in my C++ program. I want to have a variable that can use for all the void and not only in a simple void.Is it possible?
View 17 Replies View RelatedI write these code in 2 different ways and I get the same result. I just want to make sure that they both are for declare a pointer using "auto"
The first one:
int varName = 10;
auto var1 = &varName;
cout << var1 << endl; //prints, varName address
cout << *var1 << endl; //prints, varName value
The second one:
int varName = 10;
auto *var2 = &varName;
cout << var2 << endl; //prints, varName address
cout << *var2 << endl; //prints, varName value
It doesn't matter if I put dereference operator or not, I still get the same result. I just want to make sure that var1 and var2 are both a pointer.
I am getting this error while trying to compile my program:
It says that my variables "nome, cognome, eta..etc" are being used for the first time in my "inserisci" function.
I tought that I could just declare them as global in my structure like I did in my code, but apparently this doesn't work.
Do I really need to declare them again outside of my structure? Isn't there another way?
Here is my code:
#include <stdio.h>
#include "readline.h"
void inserisci(void);
struct impiegato{
char nome[20];
char cognome[20];
int eta;
[code].....
I am using Qt Creator with VS2012 compiler.
I declared a QByteArray variable : T
I initialized it. Everything OK. I added the line :
Code:
T += "
";
What follows gives me an exception and I think that the issue comes from this added line. As I take a look at T in the debugger, I don't see any but a point .
I've been messing around with loops/functions and basic logic and come up with a small maths program. Here it is:
Code: #include <iostream>
#include <string>
float divide (float x, float y) //function to divide numbers {
return x / y;
[Code] ....
Would initializing the string 'anotherGo' to a value that makes the loop run at least once be a suitable way of doing this rather than using a do/while loop? I read that a do/while loop is a black sheep but I have come across a number of uses for it. Maybe it is just preference which one you should/could use?
In C how can I initialize a variable that is not a letter or number? For example with a number I can :
Code:
int i = 5;
for ( i = 0; i <=5; i++ );
printf( "%d", i ) This would display a row of 5's
but what if I wanted to display a row of -----? What I am trying to do is read in a simple txt file, around the file I want ----1----2-----3 ect ect on the top ----a----b-----c down the side Then I want to be able to change the file at lets say position c2 and save it. This is the early stages of my attempt to set up a editable table.
I am trying to learn how to declare a pointer to an array of characters. And here is the code i have written. But iam getting a warning saying assignment from incompatible pointer type p = s.
Code:
#include <stdio.h>
int main(int argc, char *argv[]) {
char (*p)[10]; // pointer to an array of 10chars
char s[10] = "Hello"
p = s;
printf("%s",p);
return 0;
}
I am trying to store data in a struct to be able to read it latter . have problems initializing this.
struct FoodAndDrink {
struct Food {
char* CannedGoods[2] = {
"Canned Spaghetti",
"Canned Tuna",
[code] .....
I wrote the following program to initialize a string after the variables is declared, but it isn't working. A warning is given by the compiler, and the execution of the program shows a strange string. How do I initialize variable word in a separate statement from its declaration?
Code:
#include <stdio.h>
int main( void )
{
char word[20];
*word = "Hello";
printf( "The string is %s.
", word );
return 0;
}
I'm trying to write a program which prints a table of ASCII chars, I'm not really done with my thoughts on it but I already
ran into the following error:
Error: cannot initialize a variable of type 'char' with an rvalue of type 'char (*)[16]'
Here's my code so far:
# include <iostream>
using namespace std;
int main() {
char asciiTable = new char[8][16];
int nextSign = 0;
[Code] .....
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);
[Code] ....
I am trying to run a programme implementing a function with structures in c... which is:
#include<stdio.h>
#include<conio.h>
struct store {
char name[20];
float price;
int quantity;
[Code] .....
what happens to pointer pt when string s is reallocated to accommodate bigger size? does it updates itself or does it points to previous s which is not used anymore?
#include <iostream>
#include <string>
using namespace std;
int main() {
string s= "aa";
[Code] ....
Should i never return a pointer to a local variable. i have seen the following code in the standard text book.
Code:
struct node *add_to_list(struct node *list, int n)
{
struct node *new_node;
new_node = malloc(sizeof(struct node));
// some code here
return new_node;
}
new_node is a local pointer then why is he returning the new_node? Is it wrong or am i failing to understand something?
I am stuck at a problem where I have two pointers pointing to the same object, and I need to change an int on one of the pointers but point to the same object.
To be more specific, there is an array of Item objects. A long list of items a player can buy. Then, there is the player's inventory, a vector pointer. Whenever a player buys an item, it sets the pointer to the bought object.
The problem arises when he buys two of the same object. I tried to identify the objects with an ID, but it does nothing, because they are just pointing to the same object, and so I have no way of telling them apart.
This is further complicated by the fact that it is a polymorphic object. So, I can't simply make a new every time I buy an object, without making a hassle. Well, at least I am not familiar with that kind of code just yet.
Suppose you a class declared with a pointer initialization variable. When writing the copy constructor, how would one make a deep copy of the pointer variable? Can it be done in the same manner as automatic variables i.e. in the initialization list or in some other manner?
I am using C++ 11.
In the code below:
void test(int * i) {
i = new int;
*i = 10;
cout << "i: " << *i << endl;
[Code] ....
The outuput is:
i: 10
t: (some memory position).
If I really want to allocate an integer variable to t, i need to modify the void test(int * i) procedure to void test(int *& i).
I don't understand how my code not run.
#include "stdafx.h"
#include<iostream>
using namespace std;
struct student{
char name[30];
char birthday[20];
char homeness[50];
float math;
[Code] ....
I'm writing a delete function for a linked list, and I'm having issues with this bit of code:
void deleteNode(int data){
node* del = NULL;
t = h;
n = h;
while(n != NULL && n->_data != data){
t = n;
n = n->next;
}
}
Or more precisely, this portion:
&& n->_data != data
n is my new node variable, _data is the storage variable in the private section of my class, and data is the information being searched for that needs to be deleted. Everything works without this section of the code. My assumption is that n->_data is somehow wrong, but I don't see how. I've tried everything I can think of- using parenthesis, using the variable rather than the pointer, I've tried expressing the pointer in a different way, I've tried using my t variable rather than n, and I've found examples online that use this exact same expression without any issues.
I am having following pointer variable declaration
Code: Static double (*funcs[]) (double) = { sin,cos,tan,asin,acos};
Here funcs is an array of pointers to functions which take double as input and gives double as output with static as storage type am I right.
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.
View 4 Replies View RelatedHow can I add the variable adress to a void pointer inside of a class?
class variant2 {
private:
void *Vvariant=NULL;
public:
template<typename b>
variant & operator = (b *adress)
[Code] ....
if possible i want avoid the '&' when i assign the variable address.(variant2 f=varname;//like you see i don't use the '&')
for the moment i just need put the address to Variant pointer. but i receive several errors .