I have a simple question. Can a pointer be incremented in a for loop? In my program, I use a pointer variable and use it in a for loop like such:
for(*var1 = 1; *var1<100 ;*var1++)
int function(int* var1) {
if(*var1 blah blah)
{do blah blah}
if(blah)
{blah}
}
}
The variable is not incremented by the ++ even when the if conditions are not met and the loop shouldn't break. the *var1 stays at 1.
The point of this program is to calculate how many cents the user would have after a certain number of days. The user is given .01 cent on day one, and this amount is doubled with each passing day. I cannot seem to figure out how to add all of the results. Currently, my program simply outputs them to the screen. How do I tell it to add all of the results and store the sum in one variable?
#include <iostream>
#include <cmath>
#include <iomanip>
int main() {
using namespace std;
float totalF = 0;//total amount earned after number of days specified by user have passed
[code]....
I have 3 arrays named: abee1 , abee2, myarray.
I have loop that want to call abee1 , abee2 one each time and copy myarray into it . It means that I reach the name of abee1 to abee2 in the loop for doing this. I made the name of each one by using strings ( abee1 , abee2) in the loop. In the last I want to copy the myarray into the abee1/2 using pointer.
I do not know what to do after the line "string arrayname = "abee" + String;".
#include<iostream>
#include<string>
#include <sstream>
using namespace std ;
int abee1 [4] [4] ;
[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 getting and infinite loop for loop pointer variable current which points to head and is incremented by current->next in while loop. I use the pointer variable the same way in my display routine and it works. Here is listing of code.
#include "stdafx.h"
#include<iostream>
struct node{
int data;
node *next;
[Code] .....
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
bool deleteNode(struct node *head, struct node *delptr)
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);
#include "stdafx.h"
#include<iostream>
struct node{
[Code].....
I am attempting to implement function pointers and I am having a bit of a problem.
See the code example below; what I want to be able to do is call a function pointer from another pointer.
I'll admit that I may not be explaining this 100% correct but I am trying to implement the code inside the main function below.
class MainObject;
class SecondaryObject;
class SecondaryObject {
public:
[Code]....
We are making a program--but every time we input a value for scanf, the following for loop does not work and the program quits without displaying the for loop's function. We are not getting any errors.
View 11 Replies View RelatedI 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");
[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 have a function:
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"
What's the correct way of implementing this?
I have tried to submit this topic before but i didn't submit my whole code and it was removed. So here it is. All I am trying to do is load form2 from form1 then back to form1 from form2 for a certain number of times the get out of the loop. I am new to C-Sharp and it seems as though I cant seem to figure out a way to do this.
Here is form1 and form2 code. I have commented out a few things I have tried.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
[Code]....
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"
Code:
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DATA 100
int find_average(char *iden, ...) {
[Code]...
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 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++)
[Code]...
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.
I have the following code :
Code:
#ifndef TDYNAMICARRAY_H
#define TDYNAMICARRAY_H
namespace Massive {
template<class T>
T **AllocateDynamic2DArray(int nRows,int nCols)
[Code] .....
I wish to know how to traverse or loop through a dynamic 2D array using pointer to pointer as returned by the code above. Like I would in a static T[20][20] 2D array.
Code:
#include <stdio.h>
#include<ctype.h>
void try5t(){
char choice;
int choiceint;
[Code] .....
Loop is repeated an additional time as shown in the screenshot:
I'm trying to call a function via a function pointer, and this function pointer is inside a structure. The structure is being referenced via a structure pointer.
Code:
position = hash->(*funcHash)(idNmbr);
The function will return an int, which is what position is a type of. When I compile this code,
I get the error: error: expected identifier before ( token.
Is my syntax wrong? I'm not sure what would be throwing this error.
I create an instance of a base class (not derived class) and assign it to base class pointer. Then, I convert it to a pointer to a derived class and call methods on it.
why does it work, if there is a virtual table?
when will it fail?
// TestCastWin.cpp : Defines the entry point for the console application.//
#include "stdafx.h"
#include <iostream>
class B
{
public:
B(double x, double y) : x_(x), y_(y) {}
double x() const { return x_; }
[Code] ....
"
#include <stdio.h>
struct datastructure {
char character;
};
void function(struct datastructure** ptr);
[Code] ....
These codes give these errors:
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
These errors are related to
"
*ptr->character='a';
printf("Ptr: %c",*ptr->character);
"
I want to access "character" data inside the structure "trial" by a pointer to pointer "ptr" inside function "function",but I couldn't find a way to do this.
Is this the correct format to point a pointer (pointer1) to another pointer (pointer2)?
&pointer1 = &pointer2
I am kinda rusty when it comes to pointers ...
I'm trying to store an array of vectors using a double pointer as a 2D array, but after the first "vector" (column) has been filled, I get a segfault. I correctly included all the libraries needed, and declared all the variables; I am using this function to allocate the space for the array:
double **vec_array(int rows,int clms)
/*allocates a double matrix with -rows- rows and -clms- columns */
{
int i;
double **m;
[Code].....
I get no error while compiling, but when I run the program I get a segfault right after having read the first vector: switching on the check I get in my output just the components of the first vector and then the segfault:
Terminal:
$ ./myprog input_data.dat
0.000000 0.512468 -0.152468
Segmentation fault (core dumped)
Given a for loop:
int i;
for(i = 0; i < 1000; i++)
;
How many nanoseconds, or microseconds or milliseconds does it take for each iteration? And why do some use it as a timer mechanism?
I already made a nested for loop into a while loop (below this) and now I'm trying to make the outer for loop into a do while loop, but it's not working.
#include <iostream>
using namespace std;
int main () {
int len;
int j;
int i;
[Code]....
And I can't make this code do the same thing. It stops after one loop, instead of continuing to the end. Why won't the loops continue?
#include <iostream>
using namespace std;
int main(){
int len;
cout << "Enter a number: ";
[Code] ....
I need to convert the following while loop:
count = 1;
while (caloriesForItem != 0, count != numberOfItems )
{
cout<<"Enter the calories: ";
cin >> caloriesForItem;
totalCalories += caloriesForItem;
count++;
}
This is what I have come up with:
totalCalories += caloriesForItem;
for (count = 1; caloriesForItem != 0; count != numberOfItems)
{
cout<<"Enter the calories: ";
cin >> caloriesForItem;
count++;
cout << "Total calories eaten today = " << totalCalories << endl;
}
However the output is not the same?