I'm familiar with the concept of int in the for loop. However, I've seen a case where the condition for the for loop is a pointer. How is the pointer used or interpreted in the for loop condition in C or C++.
As an example:
Code:
void printer(char *fmt, ...) {
va_list args;
char *p, *sval;
int ival;
double dval;
va_start(args, fmt);
for(p = fmt; *p; p++) {
if(*p != '%') {
putchar(*p);
continue;
[Code]....
Set an Array (a[10]) and a Pointer to that array (*pa) and code a loop (for( ; ; loop) that will advance that pointer (*pa) and will set a new content into it with each loop. that means that in the end of the day, my program will automatically set content to each cell of the array by promoting the pointer by 1 and add the sum to that pointer.
When I run the program it prints the address of the cells instead the value of it.
Code:
#include <stdio.h>
void main() {
float a[11], *pa; // Array and ptr set.
int i; // counter for the loop.
pa = a;
for (i=0 ; i<=10 ; i++) // the loop itself.
[Code] .....
I'm taking an intro to programming course and my assignment is to Write a very simple program that uses two for loops and ONLY pointers and pointer arithmetic (NO other variables are allowed) to display a palindrome forward then backward. Declare the palindrome as follows: char str[] = “Straw Warts”; Well my prof never did anything with char arrays and I can't quite fit make the pointers work in the loop. This is my code. It runs how it should, i just can't seem to make a working for loop. It always says that you can compare int and char
#include <iostream>
using namespace std;
int main()
{
[Code]......
I wanted to display the correct output by using a for loop at the end of my code, but for some reason it's not working correctly.
#include <iostream>
using namespace std;
int main() {
int* ipArray[3];
for(int i = 0; i < 3; i++) {
ipArray[i] = new int [5];
[Code] .....
What I wanted to do is pretty much match my 1st out put like 0 1 2 3 4 but my 2nd output only outputs 24's and I don't know why
I have a C-Power5200 driver. I want using the C# language change to the controller's IP address.
Here a link to the website and API.C-POWER 5200
In Annex API controller.
Using the C # programming language LED controller through which controls the array is connected to the controller via the RJ45 port. I already know the basics, I mean specifics, ie
Using the instructions and DLL included with the hardware, I want to read data from it, but I can not deal with it.
Model controller is "C-Power5200" and dll is "CP5200.dll".
I would like to:-pick the data-display-edit and - save in the controller.
To read the data I am using the function
CP5200_Net_Read (BYTE * pBuf, int nSize);
and to save
CP5200_Net_Write (const BYTE * pBuf, int nLength);
I am trying to have a program that I am writing detect a controller and then say whether there is or is not one connected. But I am getting a lot of errors(25 actually) . Here is my code:
Code:
#include <stdio.h>
#include <Xinput.h>
#include <stdbool.h>
#include <Windows.h>
void main()
[Code] ....
puts("Error no controller was found on any port");
return 0;
}
I know how to create your basic programm that compiles as a CLI or exports and/or saves data to a .txt file... But how does one build a GUI?
I ask because I am currently working on a programm for my Arduino controlled robot, in which I want to have a virtual on screen controller next to a map of my bots path.
This project is for an embedded micro controller. In the project i wrote a class that generically services uarts. then i declare 6 objects of that class and hand them configurations for each specific uart.
internally all the objects have a send buffer of data that is still to be sent that gets populated by the object member function.
how can i make an array of function pointers that can point to the same member but of six different objects.
for example (not a working one)
class uart {
private:
struct myData {
unsigned char data[20]
int head
int tail
int count;
[Code] ....
I was trying to write a character controller but when I went to add my pointer to my character I get error
C2143: syntax error : missing ';' before '*'
I've looked at all my classes involved but I don't see any errors and Visual Studio doesn't report any other specific errors. Is there any way of finding the source of this type of error?
how to manually control the temperature of High Power Leds using PID controller. I have two GUIs,one reads the temperature from the Led while the second is used to ON/OFF the Leds and at the same time controls the Led brightness using slider control.The GUI that reads the temperature has a PID controller application on it.The output from this controller is what i want to use to increase or decrease the Led brightness which invariable changes the Led temperature.How to go about using this PID controller to control the Led brightness is what i have not been able to grasp well.The slider on the GUI is scaled from 0% to 100%.My thinking is that the output from the controller should be in percentage which will make me to adjust the slider accordingly.My question is that will this type of arrangment produce an output that will efficiently control the Led brightness. how to accomplish that. Attached to this post is a modified code of a tutorial on PID controller which i found on the net. a tutorial on how to develop a graph. i wish to display the Setpoint,Process value and the output value on a graph.
View 2 Replies View RelatedI am writing a program to map keyboard and mouse to an xbox 360 controller with win32 and xinput. I have everything going fine but when im trying to control the mouse with the thumbsticks I get problems with the movement if my program has the focus it moves fine but when I put another window in focus the movement is over sensitive here is the code I am using
Code:
if(_controllerState.Gamepad.sThumbRX >= XINPUT_GAMEPAD_RIGHT_THUMB_DEADZONE) {
GetCursorPos(&mousepos);
profile->Buttons[6]->input.type = INPUT_MOUSE;
[Code] .....
I have tried everything to fix it.
I'm trying to create an array of pointers to pointers which will point to array of pointers (to strings) I tried
Code:
int i;
char *string[]={
"my name is dave",
"we like to dance together",
"sunny day",
"hello",
[code]...
the app keeps crashing , I don't know how to make the array-elements to point to another array-elements..
I am a little confused while comparing char pointers to integer pointers. Here is the problem:
Consider the following statement;
char *ptr = "Hello";
char cArr[] = "Hello";
When I do cout << ptr; it prints Hello, same is the case with the statement
cout << cArr;
As ptr and cArr are pointers, they should print addresses rather than contents, but if I have an interger array i.e.
int iArr[] = {1, 2, 3};
If I cout << iArr; it displays the expected result(i.e. prints address) but pointers to character array while outputting doesn't show the address but shows the contents, Why??
I'm trying to write a function that takes a 32bit address and a data to store at this address.
I'm wanting to take the 32 bit memory address eg 0x12345678 and split it
into 4 x 2 bytes
12, 34, 56, 78
then each of the 4 entries is at most a 256 entry array.eg
FF, FF, FF, FF
So in this example, 0x12 points to 0x34 in the second array, which points to 0x56 in the third array, which finally points to 0x78 in the last array. This last array holds the actual data.
After successfully doing 0x12345678, say I might get a read for 0x1234AABB. So, the first and second pointers already exist, but I then have to create and write to dynamically created arrays.
The arrays need to have all entries set to NULL so that i know whether to follow the pointers to overwrite a previously entered value or create new arrays and pointers.
It all looks good and simple in the pseudo code I've written up but I'm having trouble coding it. I'm currently trying to deal with the first entry case, ie all array elements are NULL, but I'm getting confused with the pointers and creation of new arrays.
void cpu::store(unsigned int mem_add,unsigned int mem_val) {
int first = (mem_address&4278190080)>>24;
int second = (mem_address&16711680)>>16;
int third = (mem_address&65280)>>8;
int fourth= (mem_address&255);
[Code] .....
A1 has been declared as
int* A1[256] ;
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 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]....
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:
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?
give me a few solid examples for when one should use pointers.
View 14 Replies View RelatedThe first sample program that I am reading on the book has the following code:
Code:
* Demonstrates basic pointer use. */
#include <stdio.h>
/* Declare and initialize an int variable */
int var = 1;
}
[code]....
Is this a compiler error or is there a proper syntax for pointers using the gcc compiler?
So when if you want to change the values themselves for example in an array (just for example) this is valid;
void test(int* test)
{
test[0] += 10;
}
int bob[] {1, 3, 5};
If you did that bob[0] would not equal 11. All well and good right?
Now if you do this?
int sally = 33;
test(sallay);
This wouldn't work at all you actually have to use
void test(int& test)
{
test += 10;
}
how the memory addresses etc. are working here? I don't understand why you need to use & the reference operator if it's not an array? Why wouldn't that still work?
Alright, after what seems like forever I'm on the last stage of modifying my Payroll Program. This time I have to sort using pointers and I only have to sort the Net Pay category.
Using one of my earlier programs I've removed content from it until it's in a state where it runs but contains no sorting functions.
So now I've to a working program that lacks any kind of sorting and looks like this.
#include <iostream>
#include <fstream>//file input output stream
#include <iomanip>
#include <string>
using namespace std;
//function prototypes
int readalldata(long int id[], string fname[], string lname[], int hoursworked[], float hourlyrate[], int n);
[Code] .....
My hints for how to add pointers to the program are...
int *np,tmp;
for (i=0,i<n; i++) np=&netpay[i]; //associating the netpay to np;
temp=np[i];//storing the pointer to a temp
I've been fooling around trying to sort the Net Pay by pointers using these hints for a bit now and I'm still not getting it.
I have a problem. I want to set pointers to a default value for both 32 bit and 64 bit compiles. The 32-bit version works as:
enum constants { UNDEFINED = 0xDeadBeef }
if ((unsigned long)ptr == UNDEFINED)
but I can't seem to extend this to 64-bits. I've tried
#if __SIZEOF_POINTER__ == 4
enum constants { UNDEFDATA = 0xDeadBeef };
}; // enum constants
#elif __SIZEOF_POINTER__ == 8
enum constants { UNDEFDATA = 0xDeadBeefDeadBeef };
#endif
with:
if (ptr == UNDEFINED)
but get a message saying the '==' is undefined (I understand this)
Is there any way to setup so that I can change the size of my constants so that the comparisons will always work correctly? I've tried a 'typedef' but the compiler complains at
'typedef unsigned long long ADDR' // won't accept, and
static const SlipCellBase * const TEMPORARY = (SlipCellBase&)0xFFFFFFFFFFFFFFFF; // illegal conversion
enum doesn't work (because it's an int?)