C :: Make Array Which Contains Arrays But With A Variable Size
Jan 29, 2015I am wondering how I could make an array which contains arrays, but with a variable size.My first try..
Code:
int array[][] = {{1}, {2}};
But this isn't proper
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C++ :: Storing Variable Size Pointers Array As Class Variable
Mar 2, 2013This problem is best explained by looking at its output below. I stored 15 different values but when retrieved some are wrong.
#include <iostream>
using namespace std;
class A {
public:
int ** pointer;
[Code] ....
I need to store and retrieve the 15 different values correctly. How to solve this? The main thing is, I need to store the pointer in class A objects.
C++ :: How To Insert Array Size As Variable
Nov 30, 2013How do I insert a array size as variable?
View 5 Replies View RelatedC :: Size Of Struct With Variable Length Array?
Mar 6, 2015The WinAPI has a struct like this for raw input:
Code:
typedef struct tagRAWINPUT { RAWINPUTHEADER header;
union {
RAWMOUSE mouse;
RAWKEYBOARD keyboard;
RAWHID hid;
} data;
[code]...
The definition of the struct doesn't show it but the documentation says that bRawData is variable length. sizeof(RAWINPUT) will not be the correct size when the data field is of RAWHID type so how do you allocate a variable with automatic storage type that has the right size for the entire struct? You can get a header that has the size for the entire struct but how do you actually allocate storage space for the data without using malloc? I've seen some example code that used a char array but that violates aliasing rules and there are also alignment issues with that approach.
C++ :: Static Array Variable Size Allowed?
Mar 1, 2013I have a function like this
void foo( int i) {
...
uint8_t buf[ i];
...
}
And I don't understand why the compiler is not complaining... I'm using g++ -c -g -Wall to compile ....
C :: Declaring Array Size Using Variable Causes Program To Crash
May 10, 2013I am new to C. I've been trying to use C to code some statistical functions originally coded in R. I've encountered an interesting phenomenon. In the function foo1, I declared the array v1v2b using an actual value 1999000. The function runs fine when I call it in R.
Code:
void foo1(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
outer_pos(x, y, nsamp, &v1v2[0]);
double v1v2b[1999000]; //<-------HERE
for(i=1; i<= 1999000]; i++){
v1v2b[i-1]=1;
} }
However, in foo2, I first create an integer variable called index, and store the value 1999000 in it. I then use it to initialize the same array. When I tried calling this function in R, it either led to a stack overflow error, or completely crashed R.
Code:
void foo2(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
[Code] .....
C++ :: Default Constructor - Set Array Of Strings To Null And Size Variable To 0
Dec 7, 2013For my default constructor I need to set an array of strings to null and the size variable to 0. Here is my code for that
DynamicStringArray::DynamicStringArray() {
*DynamicArray[]=NULL;
size=0;
}
When I try and compile it I get an "expected primary expression before ']' token" error.
C++ :: Insert Variable For Size Of Array And Prompt User To Insert Elements
Dec 1, 2013how to insert a variable for the size of array and prompt user to insert the elements for the array?
View 13 Replies View RelatedC :: Can Make 2 Different Size Structures In A File?
Nov 29, 2013I was wonder if I can make 2 different size structures in a file. I wrote a code but It's apart of my school project and I havent compiled it yet, so Im just wondering will this work?
Code:
if((stsPtr = fopen("status.dat", "rb")) == NULL){
prinft("File could not be created/opened.
");
Error();
[Code] .....
C++ :: Arrays Are Actually Created With A Size Indication?
Jan 14, 2014Reading Effective C++ by Scott Meyers, and Item 16 claims that when an array is created, the compiler reserves a block of memory at the very beginning to indicate how many objects are in the array.
n = number of objects
|n|index0|index1|...etc
Scott Meyers wrote:This is just an example, of course. Compilers aren't required to implement things this way, though many do.
Supposedly, this how delete knows how many objects to destruct. And if you were to do something like:
int* foo = new int;
//Stuff
delete[] foo;
Then delete would interpret the first block as the number of items to destruct, then continue on and destruct that many blocks of memory onward, causing UD behavior.
Is there any truth to this?
C++ :: Table Of Variable Size?
May 10, 2014I would like to create a table but I dont know how big. Thats why I want to use variable to describe its size. Something like that:
int x = 5; //I will use a function to set x
int Table[x];
What should I do to make it work?
C++ :: Read N Data Items Into Two Arrays (X And Y) Of Size 20
Apr 1, 2013Trying to do a homework assignment for a class and how to read a file into an array. I've looked in our book and on several other forums and cant seem to find any examples of this. Below is the assignment I'm working on. I have a shell of the program that I can get to run, but getting a .txt file to read into an array is something I cant seem to figure out how to do.
Write a program to read N data items into two arrays, X and Y, of size 20. Store the product of the corresponding pairs of elements of X and Y in a third array Z, also of size 20. Print a three column table that displays the arrays X, Y, and Z. Then compute and print the square root of the sum of the items in array Z. Compute and print the average of the values in array Z and print all values above the average of array Z. Determine the smallest value in each array using only one function.
Use the two data files named DATAX.TXT and DATAY.TXT.
You must use functions for the reading of the data, computing the average, printing the three column table and printing the values above average.
C/C++ :: Functions Passing Size Of Arrays As Value Parameters?
Mar 11, 2014we were given this code:
// Music Shuffle Program
// This program takes an array of strings and randomly permutes their order.
// This allows us to generate new song shuffles.
#include <iostream>
[Code]....
or are they referring to something else?
C++ :: Limit Size Of String (arrays And C-style Strings)
Dec 9, 2014how do I tell the if statement to output this error message 'exceeded the maximum amount of characters' that has its characters stored in an array using c-style string?
[INPUT] The cat caught the mouse!
[OUTPUT] Exceeded the maximum amount of characters (max 10)
#include<iostream>
#include<string>
[Code]....
C/C++ :: Store Initial Size Of List In Int Variable?
Nov 24, 2014I've been trying to store the inital size of a list in an int variable, so I can access it later in case I modify the list size. For example, I did the following:
std::list<AType *> myList;
myList.push_back(anATypeobject);
int initListSize = myList.size(); //initial list size
myList.push_back(anotherATypeobject);
myList.push_back(yetanotherATypeobject);
while(myList.size > initListSize)
myList.pop_back();
What this is supposed to do is to get an initial size of a list, and then be able to return to that initial size. However, when I try to do it in my code, initListSize always change if myList.size() changes. Is there a way to change that?
C/C++ :: How To Make A Copy Of Pointer Variable
Mar 29, 2014Suppose 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.
Visual C++ :: Can't Make Maze Work Correctly With Arrays
Apr 30, 2014I have to make a maze with arrays, but i cant seem to move down or up or at all. Here is what I have so far
#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
[Code].....
C :: Make A Program That Multiplies Loop Variable By 2
Nov 15, 2013I have an exam in C programming I'm a little stuck on loops..I have to make a program that multiplies the loop variable by 2 then takes away 1... easy, that was a for loop no problem
for (x=3; x<=65; x=x*2-1)
that should print out 3 5 9 17 33 65 however, my lecturer has given the task for it to reverse, but not to display the number 17 on the way back down using an if statement...however, this time it must be a do while loop... This is what I have so far.
Code:
#include <stdio.h>
#include <stdlib.h>
int main()
{
int x = 129;
}
[code]....
C :: Creating Variable Length Arrays
Oct 24, 2014How do you prompt the user to enter the number of elements for the array and use that information to creatr a variable length array? And then how do you prompt the user to enter in a number for each element of the array and scan in the appropriate numbers? the numbers are double precision floating point.
for example,
Enter the numbe of elements in the array: 3
Enter element 0: 3
Enter element 1: -1
Enter element 2: 4
I know it starts with
int main() {
double N;
int a[size];
printf("Enter the number of elements in the array:" );
scanf("%f", &size);
//I'm pretty sure this is wrong
C++ :: Random Numbers Between 1 To 5 For Variable Of 5 Arrays
Sep 14, 2012I want to have the random numbers between 1 to 5 for a variable of 5arrays. for having the random numbers i am using the code as below.
Code:
for(int i=1;i<=5;i++)
{ int j=rand()%5;
cout<<j<<endl;
}
The problem with this way of generating random number is that i get the same set of random numbers in every outputs. Is there any other way to have different random numbers with many different outcomes as much as possible.
C :: Multidimensional Arrays - Variable Sized Object Maybe Not Be Initialized?
Oct 30, 2013I'm trying to get a full understanding of multidimensional arrays. When I try to initialize the array I get an error.
Code:
int Pick2(void) {
int pick = 2;
int limit = 0;
[Code].....
The error I get is "variable-sized object maybe not be initialized" with warnings messages pertaining the that Error message.
C++ :: Accept Integer Array And Its Size As Arguments And Assign Elements Into 2 Dimensional Array
Jan 10, 2015Write a program using user-defined function which accepts an integer array and its size as arguments and assign the elements into a two dimensional array of integers in the following format: If the array is 1,2,3,4,5,6, the resultant 2D array is
1 2 3 4 5 6
1 2 3 4 5 0
1 2 3 4 0 0
1 2 3 0 0 0
1 2 0 0 0 0
1 0 0 0 0 0
C++ :: Passing 2D Array To A Function Where Size Of Array Is Not Known At Runtime
Jun 27, 2014I'm wondering if it is possible to pass a 2d array to a function where the size of the array is not known at runtime.
I've tried
function ( array[][6] ) ;
But the size of the array has to be constant so it cannot be declared later.
I've tried using a template but you still have to declare the size of the array at runtime. Is this even possible at all?
The only other way I can think of is using a dynamic 2d array but how to create one and manipulate it.
C/C++ :: How To Make Multiple Subroutine And Return Multiple Arrays
Aug 17, 2014how to make subroutines and return multiple arrays.Before that, i wrote my program on matlab. could my program to be structured as following?
<header>
initial value of program;
subroutine1() {
calculating the first work;
return 2 or 3 arrays;
[code].....
C :: How To Make A Function Read From Array A But Put Select Parts In Array B
Jul 30, 2013im trying to read in 1 array and get 2 as outputs from 3 different functions.my read array is easy enough were im getting confused is how to read that array, separate it and take out only the parts i want and place them into a 2nd, then again a 3rd array.i have the following so far:
Code:
#include<stdlib.h>#include<stdio.h>
#include<unistd.h>
#define SIZE 10
}
[code]....
this compiles without a complaint, but when i go to run it no longer responds after taking the 10th element (well 9th if counting from 0).I think i have the if correct for the even odd section, but when i try to populate B or C array with the output of that if statement from A is were i think things are dying...
C/C++ :: How To Make 2 Arrays Put Them In A File Then Read Them From File
Mar 11, 2014I have to read 2 arrays, put them in a file. Then make a 2nd program, read the data from the file and show the 2 arrays. I believe I have fully completed the first program, but I am still working on the 2nd one. On the 2nd one I am trying to create a function that displays the data from the file.
//first part
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
const int num_stores = 3;
const int col = 4;
const int size=4;
void showData( const string[], const int[][col], int size );
[code]....