C++ :: Allocate Memory In A Function And Call From Main
Aug 30, 2013
So my assignment is to create a program that calls for a function in main that dynamically allocates an array[3] and then have pointers with multiple levels of indirection and pass them by reference so they are not lost after the function. Here is my code:
#include <iostream>
#include <array>
#include <iomanip>
#include <string>
[Code]....
Next part is to ask user for two non-negative numbers and then get the length of those numbers and create an array. for the size of each number they input. Then to separate those numbers and add the cross-sums.
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Nov 8, 2013
I am trying to make a function that allows me to allocate memory to a "mem" variable and setting each of its chunk's status to FREE. FREE is defined as 0. Below is my code of the function.
Code:
int allocate(mem *mm, int num_chunks, int chunk_size) {
int i;
mem *temp;
if((mm = (mem *) malloc((num_chunks + 1) * chunk_size)) == NULL){
perror("Failed to Malloc
[code]...
mem; If my function works the way it should, it should print out five 0 because that is how I set them in the function, but this is not the case. I've looked at my function for 2 hours, but I could not figure out any logical error. Now, I think my problem lies with my limited knowledge of pointer arithmetic. On the other hand, when I insert 1000 as the second argument into my function, it gives seg faults, which is not the case for smaller values like 5, 10, 15, etc.
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May 26, 2013
I'm trying to return a string to then call it on main function.
Code:
const char* coiso(int chave){
char str [50];
sprintf(str,"%d",chave);
char txt[50] = ".txt";
strcat(str,txt);
return str;
}
int main () {
const char* info = coiso(8);
printf("%s",info);
}
If I do a printf("%s",str) in coiso function it works but the following code doesn't work.
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Apr 29, 2013
How to ADD a call to the FindMostExpensive function AFTER the main display loop, and use the index returned to display the information about the most expensive car?
// Session7.cpp : Defines the entry point for the console application.
//using struct
// reading from file
// using functions
#include "stdafx.h"
#include <iostream>
#include <iomanip> // only used to tidy up the console output here
#include <fstream> // added file handling
[Code] .....
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May 5, 2014
i have this program I am working on and it seems to crash after the function call getdata()
here is the code
#include<iostream>
#include<string>
#include<cstdlib>
[Code].....
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Feb 2, 2015
I'm writing code to create an array of integer and let user input choice to display, replace, add new element, etc.I created a header file in the header file there's a function:
Code:
int display_one_element(int* array, int num_of_elements, int position) {
if(num_of_elements < position || position < 0) {
printf("Position out of bound.
");
return 1;
}
return array[position-1];
}
in main I write a function call:
Code:
display_one_element(array, *p_num_elements, position);
My code seems to work fine but there's an error message right next to my function call:
1.too many arguments provided to function like macro invocation
2.Expression result unused
I tried to move the function from header file to c source file. but other functions in the header file works fine and this doesn't work with the error message.
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Mar 16, 2013
What would be the correct way to call a function within main that has file pointer parameters?
function prototype: Code: void CalculateBoth(int num1, int num2, int*sumPtr, int *diffPtr);
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Jun 4, 2013
Code:
#include <stdio.h>
#include <stdlib.h>
int size_b_row1;
int size_b_col1;
[Code].....
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Feb 16, 2013
I am getting call of nonfunction in function main <> error and 's' is assigned a value that is never used in the function warning...
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main() {
float a,b,c,s,area;
[Code] ....
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Jun 4, 2013
#include <stdio.h>
#include <stdlib.h>
int size_b_row1;
int size_b_col1;
int main(void) {
double C[4][4] = {{1,3,5,2},{7,6,2,2},{1,2,7,3},{2,3,5,3}};
double TC[4][4];
transpose(C, TC);
[Code] ......
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Oct 25, 2013
I'm currently learning templates -- & my logic is in a knot with what I am trying to do which is the following:
-Create a function name load
-Accepts a filename (the filename is a text file of integers)
-Open the file
-Create an array(dynamically allocating an array) filling it with the elements read in from the file & returns the array(so that the return type of the array is a pointer to the element type of the array).
//Header file:
#ifndef BUBBLE_SORT_H
#define BUBBLE_SORT_H
#include <iostream>
template <typename T>
void load(std::string filename, T *&arr, int *size);
[code].....
how to allocate memory when it comes to using templates..
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Jan 13, 2013
what i want to do is if memory allocation fails it display a message shown in the example but its not working
vehiptr = new VEHICLE[vnum];
if(vehiptr == 0)
{
cout<<"Failed to Allocate Memory"<<endl;
return main();
}
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Mar 8, 2014
I’m writing an application for raw image processing but I cannot allocate the necessary block of memory, the following simple code gives me an allocation error.
double (*test)[4];
int block = 32747520;
test = new double[block][4];
off course with smaller block size (i.e. int block = 327475;) it works fine. Is there an allocation limit? How it is possible to deal with big blocks of memory?
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Sep 24, 2014
I CANT use std::string, classes, constructors for this project. I am required to use this archaic method of c-style strings with dynamic memory allocation occurring outside the struct.. i know its not the best way to go about this, but there's nothing i can go. I have a struct:
struct card {
char *suit;
char *rank;
int cvalue;
}
I've created a pointer of size 52 for my deck
card *deckPtr = new card[52];
card *deckHome = &deckPtr[0];
I then try to use
for(int i=0;i<52;i++) {
(*deckPtr).suit = new char[8];
(*deckPtr).rank = new char[7];
deckPtr++
}
deckPtr=deckHome;
I am essentially trying to fill in these arrays from a card file, but I cannot make it past running the program, i get sa seg fault which I dont understand why.
I dynamically allocate memory in my card read in function..
void cardInit(card *deckPtr) {
card *deckHome = &deckPointer[0];
ifstream fin;
char *finName = new char[13];
cin >> *finName
fin.open(finName)
[Code] ....
Its a pretty simple program..and my dynamic memory works for the file name, but I cant figure out why it doesnt work for structs?
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Nov 5, 2014
There is a part in the lesson that explains how malloc is used to allocate free memory to a pointer and gives us 2 examples:
Code:
float *ptr = malloc( sizeof(*ptr) ); and Code: float *ptr;
ptr = malloc( sizeof(*ptr) );
From my logic in the first case we allocate the memory to *ptr and in the second to ptr.
It's a bit confusing, am I missing something?
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Jun 13, 2014
Consider this program:
Code:
// sb_string class v1.04
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct sb_string {
[Code] ....
And here is the output I got:
Code:
[harshvardhan@hari-rudra] ~/Desktop% gcc49 -o test test.c
[harshvardhan@hari-rudra] ~/Desktop% ./test
-before Value of len = 1
(in_function)-before Value of len = 1
(in_function)-after Value of len = 1
-after Value of len = 1 I was trying to make a little easier to work with string. Once the memory is allocated by malloc via sb_init() function, the sb_massacre function wasn't working to deallocate the memory. I had used multiple versions of gcc and clang but the result is same.
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Jan 2, 2013
A special hardware unit with some storage in it is connected to your computer and is memory-mapped so that its storage is accessible in the address range 0x55500000 – 0x555fffff. You want to interface this hardware unit to your C++ program so that dynamic memory is allocated in this hardware unit, not in your computer’s memory. Implement a class MyHardwareMemAllocator which has the following function.
void * allocMemoryInMyHardware(int numberOfBytesToAllocate);
which returns a pointer to the allocated memory chunk, or null if unable to allocate.
C library calls like malloc are not allowed.
1) How to allocate memory from given address range.
2) How to check whether this required memory space is available or not for allocating
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Apr 9, 2012
I use the array of Radiobutton,string,.. in my project. How i can destruct these array from memory,because i see the stackoverflew exception.
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Jan 24, 2013
I created a structure containing two variables of type char.
i.e. char name[64],char details[128];
And a pointer to structure now when I write this name and details to file and now I want to change the particular name.
i.e. To modify then if the stored file name is greater than the entered name then it is erasing the next record line also I need to allocate some memory.
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May 11, 2012
I have a question about the KLU library for LU factorization of sparse matrices. The KLU library accepts a pointer to a memory allocator function, by default it is malloc(). Then it uses this pointer to allocate the memory required.
I want to extend the library and I now have object of classes. I want to use the operator new instead of malloc to allocate the memory. In the same time I want the new operator to call the constructors of the objects. Is there a way to do it?
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Apr 25, 2014
What is Function call Overhead and Function Call Stack?
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Jan 26, 2013
I have a program which call only one time malloc at the start of the program. When running, I see with 'process-explorer.exe' that memory is growing in little steps. Is this normal? why?
Using Windows 7
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Mar 28, 2014
look at this code:
#include <iostream>
using namespace std;
class teste
[Code]....
Each time i call "x = new teste();" the previous object is deleted? Does this code cause any sort of memory leak?
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Jan 19, 2013
Ok so I am working on a game and I'm in the process of developing my Player class. Anyways, what I have is a keyboard function that is called in my main function to make a shape move.
void myKeyboardFunction(unsigned char key, int x, int y) {
switch ( key ) {
[Code].....
But when I try to call it, trying to copy my previous method,
glutKeyboardFunc(Player1.playerControls);
I get an error
error C3867: 'Player::playerControls': function call missing argument list; use '&Player::playerControls' to create a pointer to member
I get an error saying it can't convert parameters. I would just like to understand why the arguments become a problem when I make the function a member of my class, when the first method I used is so easy.
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Jun 9, 2013
The function is supposed to return value from the file in my main, but I am getting empty value. I am trying to get better with pointer. Right now just teaching myself.
right now the only way for this code to show value is when in put the putchar(*ps) inside my readfile function. I would like to readfile to return value and print in the main function.
Code:
#include <stdio.h>
char *readfile(char filename[]);
int main(int argc, char *argv[] ) {
[Code].....
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Dec 26, 2014
I am writing a program in which a Fucntion has to be wriiten to parse the Command Line . When I include Code for parsing in main fuction iteslf ,its run ok . But I want to make a fucntion of that code and call it from main ,than it show Segmentation error .
By using Debugging I found Some thing is mess with " -m" Parameter of Command line , But Cant Rectify it ..
Code:
int main (int argc, char *argv[]){
//get_parameter_value(argc,argv);
// buffer[packet_size+1]= char ("'");
while (argc > 1) {
if (argv[h][0] == '-')
[Code] .....
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