i want to ask how does malloc works on an array for instance can i dao this
Code: p=100;
int array[10];
array = malloc(p * sizeof(int));
then will the size of int be 100 so will i be able to do like
Code:
array[11] = 12 ; ???
also if i have a 2d array how can i use malloc on it and how does this works with pointers????
My code has been acting odd. I made a function that layers my art resources but only the last tile of my art resource acts the way it should. My character goes behind and in front of the last tile and gets printed correctly. Strangely its really exclusive to the last tiles I print. What I need is to figure out in step by step order what going on with my code sample below and be able to layer the resources.
Here is a small sample of my main function. This is how I do my rendering.
Code:
Int main (int arc, char* args[]) {
//Move class
Move character;
//Class Tile & Side Tile
Tile *tiles [TOTAL_TILES];
[Code] ......
i want to write an array sorting program that works with recursive function.but i can not do it.
my algorithm
Recursive
find the min value
find the min value and save it
find the min value and save it and remove it from loop
put the rest in loop again
find the min value again
..
...
i didnt write the function because i dont know how will it work
Code:
#include<stdio.h>
#include<stdlib.h>
#define s 5
void main() {
int a[s]={25,3,2,4,1},c[s]; // c[s] for new sorting
int i,ek,j; //ek = min
[Code]....
I want to be honest, this is FOR homework, but is NOT homework. I have created this example to work from in order to understand qsort further because the next assignment requires it's use.
Our teacher gave us this small piece of example code and I am trying to expand on it to serve my purpose.
[C] Sorting - Pastebin.com
The code gives me no errors, but does not sort the array. Need to clarify the use of qsort in this instance.
I am imagining that the reason it's not sorting properly ( or at all ) is because of my comparison function. That is really just an assumption. Or perhaps I just don't understand the pointer array i'm using.
I am able to work with n instances of a structure in one mallocated area, but when I try to do the same thing with just character pointers, I get compiler errors about making integer from pointer without a cast. If I create a structure with just a character pointer in it, it works just fine... I am just not seeing something here!!!
This works:
Code:
#include <stdio.h>
#include <stdlib.h>
int main (void) {
struct items {
unsigned int item_1;
unsigned int item_2;
[Code]...
This DOES NOT work!
Code:
#include <stdio.h>
#include <stdlib.h>
int main (void) {
char * items_ptr = NULL;
unsignedint i = 0;
char * one = "one";
char * two = "two";
[Code]...
I made a program that adds two matrices and displays their sum with a max dimension of 100.
/* This program asks the user for 2 matrices called A and B, as integers,
and displays their sum, C. The max dimension of each matrix is 100. */
#include <stdio.h>
// Construct function
void construct() {
int m, n, i, j; // Variables
int first[100][100], second[100][100], sum[100][100]; // Matrices variables
[Code] ....
Now I need to change it so there is no max size for each matrix. The arrays will be larger than 100x100 so I need to use malloc to create my arrays. So I cant use int A[rows][cols]. This is what I did to covert arrays to malloc. It compiles but it crashes after I entered all the integers.
/* This program asks the user for 2 matrices called A and B, as integers,
and displays their sum, C. The max dimension of each matrix is 100. */
#include <stdio.h>
#include <stdlib.h>
// Construct function
void construct() {
int m, n, i, j; // Variables
int *first = NULL;
[Code] .....
I am attempting to change a character in a character array.In the code below, there are three attempts to do this. Only the first one will succeed. The last two both segfaults. If I understand correctly, str_one is declared in the heap, and could therefore be manipulated; and in contrast, str_two is declared in the stack and is therefore immutable, thus the segfault, when update it is attempted. However, I understand that using malloc, one is able to assign a pointer and allocate space in heap memory. Thus, I should be able to manipulate the assigned variable str_three. Doing so, however, results in a segfault.
Code:
#include <stdio.h>
#include <stdlib.h>
int main (int argc, char const* argv[])
{
char str_one[4092] = "This is string number one";
char * str_two = "This is string number two";
[Code]...
What is wrong with my function why does it spit out huge numbers? And how do i use malloc or calloc to create an array in dynamic memory, and return a pointer to this array
Code:
#include <stdio.h>#include <stdlib.h>
int fibonacci(int n)
{
int i;
long int fib[40];
fib[0]=0;
fib[1]=1;
for(i=2;i<n;i++){
fib[i] = fib[i-1] + fib[i-2];
[Code]....
I'm having a really dumb moment and I cant seem to remember how an if statement works, with only the variable name as the condition..
Code:
if(var){
//then do something
}
How the getline function works.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
[Code] ......
getline(&inputstr, 128, NULL); getline gets a line in a data file.
I assume that inputstr[128] is the name of the file? why is the number of the array in the getline function....
This is simple recursive solution of Fibonacci number:
Code:
int fibo(int n)
{
if(n<=1)
return 1;
else
return fibo(n-1)+fibo(n-2);
}
Now the recursion will generate a large recursion tree, like if n=5, 5 will call (5-1), (5-2) or 4,3 . What I want to know is, will fibo(n-1) will be called 1st go all the way to the base case 1, then do the summation or fibo(n-2) will be called right after fibo(n-1) ?
I know how exception handling works, but how should I actually use it in action? Let's say I have something like this:
Class X
{
public:
X();
//Pre-condition: example can't be 3.
void number(int example);
[code]......
If I know that the exception can only happen at the beginning of the function, is it okay to catch it right away?
I have this following piece of code:
int id = 5;
const char *ptrId;
ptrId = ( int_to_str(id) ).getPtr(); // Works in Solaris well
But the above code prints some junk values when I run the same on Linux machine. But the following works well on Linux:
String temp = int_to_str(id);
ptrId = temp.getPtr();
The prototype of getPtr() is:
const char* String::getPtr() const
Okay so I am programming an 8051 variant to interact with an SD card. In a separate initialization routine in SD_CARD.c I pull out the vital information of the card into global variables. I then call Menu() which is in another source file but includes a header file with all of the variables declared as extern. Now here is the weird, part this is from my Menu.c
printf("%u" , VOLUME_1_SECTOR);
if(VOLUME_1_SECTOR==16384)
printf("Correct");
else
printf("Incorrect");
Now the output of the first printf is 16384 but the conditional evaluates to false. If I put this code in SD_CARD.c (Where VOLUME_1_SECTOR is defined) the conditional evaluates to true. I am confused why the printf works correctly in Menu.c but not the conditional.
when i was finding a way to concatenate three integers in C, I came across a snippet like this
Code:
#include<stdio.h>
#define cat(a,b,c) a##b##c
int main()
{
int d;
d=cat(1,2,3);
return 0;
}
How the macro works here? I am unable to understand the function '#' plays in the macro.
I tried writing a program for finding the area of a circle, and I'm wondering why it only works when i define it as 'float', but not as a double?
Code:
#include <stdio.h>
#define pi 3.14159
double
main(void)
[Code] .....
Assignment: Take an integer keyed in from the terminal and extract and display each digit of the integer in English. Ex. 932 --> nine three two
Code:
/*This program takes an integer keyed in from the terminal and extracts and displays each digit of the integer in English.*/
#include<stdio.h>
int main(void)
{
//DECLARE VARIABLES
int num;
}
[code]....
I don't know how the program works if the integer is more than one digit.
I have a question about a dynamically loaded library I am using. I have called it SqlWrite, it is for connecting and writing to a Microsoft SQL server DB. I have a function in it that is defined as:
extern "C" {
__declspec(dllexport) RETCODE __cdecl SqlExecS(SQLHANDLESTR* h, LPCSTR Statement) {
RETCODE RetCode;
std::string input = Statement;
std::wostringstream conv;
conv << input.c_str();
std::wstring wCmd(conv.str());
[Code] ....
I then load it in another MSVC project as:
#ifdef WIN32//C:UsersaDocumentsVisual Studio 2012ProjectsGetPageSourceDebugGetPageSource.dll
#pragma message("WIN32 is defined")
#ifdef _DEBUG
SetErrorMode(0);
[Code] ....
As you can see, inside the prototyped function "SqlExecSP", I cout (or, rather, wcout for wide characters) the sql statement i am running, and the return code of the sql statement. a sql return code of "0" is equivalent to "SQL_SUCCESS". Then, I cout " got player again " after executon of SqlExecSP alias SqlExecS.
This usually works, and gives me following sample output:
exec SELECT [PlayerID], [FirstName], [LastName], [TeamID] FROM [soccer].[dbo].[Players] WHERE LastName = 'Abdellaoue' AND FirstName = 'Mohammed' retcode 0
RETURNING FROM EXECSP NOW!!!
got player again
However, sometimes, the program crashes somewhere between outputting "RETURNING FROM EXECSP NOW!!!" and outputting " got player again ", i.e. the output is then:
exec SELECT [PlayerID], [FirstName], [LastName], [TeamID] FROM [soccer].[dbo].[Players] WHERE LastName = 'Abdellaoue' AND FirstName = 'Mohammed' retcode 0
RETURNING FROM EXECSP NOW!!!
As you can see, it doesn't output the next line " got player again ", because it somehow crashes in between.
However,t he only line that should be executed between this, as far as I can understand, is the actual return of the DLL function SqlExecS, prototyped as SqlExecSP in my calling code, i.e. the only line that should be executed in between is:
return RetCode;
However, somehow, this fails, even though RetCode is "0", as I can see at the end of the output
exec SELECT [PlayerID], [FirstName], [LastName], [TeamID] FROM [soccer].[dbo].[Players] WHERE LastName = 'Abdellaoue' AND FirstName = 'Mohammed' retcode 0
Now, why sometimes this crashes, and sometimes this works. I.e, I can sometimes call this function x times, and it doesnt fail, outputting " got player again " right after the calls, and sometimes, it fails somewhere in between, at call x, y, or z, i.e. sometimes i can execute it ten times successfully and sometimes i can't, even though the return code is still 0, and it just fails somewhere in between. I am not sure if it has to do with the call being a call to a dynamically loaded DLL function, but I can't see where else the error is.
Why this can be failing, and at different, seemingly random times?
i've got an assigment that requires me to overload some operators and add some objects together.
I will show the code and explain as good as I can.
void SArray::operator+= (const SArray &obj)
{
Sphere * tmp_arr;
tmp_arr = new Sphere[obj.antalobjekt+this->antalobjekt]; //antalobjekt = //Gets amount of elements in the arrays.
[Code]......
m_arr is the inner array for storing elements, do ask if something is not clear enough. The copy constructor works, so i have not included it.
My program works primarily by receiving user input however; using 'char' and 'fgets' i have to stipulate how many characters i want assigned, and this isn't practical for what I am after. Example below.
Code:
char example[50];
printf("What colour is the sky?
");
fgets(example, 50, stdin); Is it possible that the assigned number (in this case '50') is determined strictly by the user input?
for example, user input is Blue then 50 is then 5?
I am trying to create a multiple choice quiz so I can learn the menu at my new job, while doing a side project but I am having a warning when outputting. Speaking of side projects, is this a kind of side project people are looking for on a resume?
Code:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
}
[code]....
My source works perfect.The problem is that the (remove(),rename()) functions works but return nonzero number, so they fails all the time.
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <fstream>
using namespace std;
int main() {
char array[100]={"1)open-write,2)open-read,3)rename,4)delete"};
[Code] ....
Whenever I try to call merge sort on large numbers say n=10000000. It gives an error. It works fine for small numbers, even though I have declared my Lists on the heap.
The below code is just the divde part.
List<long>* Merge(List<long> *ParentList) {
if((ParentList)->Length==1) {
return ParentList;
[Code] .....
I'm making a .json loader for a project that I'm working on, and to simplify things, I decided to make all the root attributes named in a separate file. Here's my problem: my loading function, Add(const char* id), works just fine when I pass it a string literal.
However, when I use a function that iterates through a vector list, even with the exact same definitions as the literal, it returns the error: std::out_of_range at memory location 0x0026fb30
I've stepped through it with the VS2010 debugger about a hundred times, checked against memory locations, and just have done everything I can think of, all to no avail..
The code, with data-checking omitted:
The std::map I'm adding to:
static std::map<const char*, Item*> *s_mItems;
Initialized as std::map<const char*, Item*> *Item::s_mItems;
Add() Function (Works by itself with a literal):
static bool Add(const char* id) {
...
std::string name = node.Get("name").ToString();
std::string desc = node.Get("description").ToString();
int rarity = StrToRarity(node.Get("rarity").ToString());
[Code] ....
AddList() function, where the program always breaks:
static void AddList(std::vector<std::string> list) {
for(std::vector<std::string>::iterator it = list.begin(); it != list.end(); it++) {
Add(it->c_str());
}
}
I was able to get this program running. Now I working on taking one of my member functions and turning it into a standalone function. I choose the create_board() function. Yet, if I declare it in my header file or my main.cpp it cant access any info from the original member functions?
main.cpp
#include "ticTacToe.h"
#include <iostream>
#include <limits>
[Code]....
I am trying to query dates between two textbox values converted to datetime in C#. The dates are returning in the correct datetime and no conversion problem exists there.
However when I run the below LINQ to SQL query in C# it returns no enumerable results. But if I take the below code:
DbCommand dc = dbHistoryContext.GetCommand(qryRes);
Console.WriteLine(dc.CommandText);
and get the results as a string of text and cut and paste that into the SQL Server Management studio and execute it - then it works. What do I need to do to search between two dates so that it properly works. The field is of format Date in SQL Server if that matters and the fields being used to pass the information to it are DateTime. The compiler doesn't show any errors but it just doesn't return results.
var qryRes = (from res in dbHistoryContext.tblR
where res.updateddate >= dtDateFrom.Date && res.updateddate <= dtDateTo.Date
select res);
