C :: How To Use Character Pointers Instead Of Arrays
Apr 14, 2013Here is my program to look up words. How do I use character pointers instead of using arrays?
Code:
#include <stdio.h>
struct entry
{
[Code].....
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C++ :: Dynamic Creation Of Arrays Of Pointers To Arrays Of Pointers
Apr 15, 2013I'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] ;
C :: Using Malloc For Array Of Character Pointers
Mar 30, 2013I 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]...
C/C++ :: Using Pointers For Character Array In For Loop
Nov 3, 2014I'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]......
C++ :: Multidimensional Character Arrays?
Jan 19, 2013I'm trying to create Minesweeper and with 2D Multidimensional character Arrays, It doesnt appear like in a grid format i want it to.
#include<iostream>
#include<conio.h>
#include<string>
#include<cstdlib>
#include<ctime>
[Code]....
C++ :: Character Sequences - Declaring Arrays?
Apr 1, 2014According to [URL] ....
" char myword[] = { 'H', 'e', 'l', 'l', 'o', ' ' };
char myword[] = "Hello";
In both cases, the array of characters myword is declared with a size of 6 elements of type char: the 5 characters that compose the word "Hello", plus a final null character (' '), which specifies the end of the sequence and that, in the second case, when using double quotes (") it is appended automatically."
However there are examples where word array is declared as :
char myword[] = { 'H', 'e', 'l', 'l', 'o' };
Is syntactically correct?? If yes, what is the size of myword? and does ' ' append by compiler automatically?
And is char myword[] = "abc" same as char myword[] = {'a','b','c',' '} or is it same as char myword[] = {'a','b','c'} ??
C++ :: Use Different Pointers For Arrays?
Dec 24, 2013So 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?
C :: Dynamic Arrays And Pointers
Feb 11, 2013I am having troubles with dynamic arrays and pointers. All the errors are of that kind. I think when I am assigning malloc to an array we assign to its address.
Code:
/*Create an array of genes of the large matrix*/
gene_t gene,gene1,gene2;
gene=malloc(INITIAL*sizeof(gene2)); Code:
while(...) {
if (gene_num==current_size){
[Code] .....
C :: Arrays And Pointers In A Loop
Jun 27, 2013Set 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] .....
C :: Merging Arrays Using Pointers
Jul 17, 2013Merging two arrays together using pointers!
View 4 Replies View RelatedC :: Accessing Arrays Using Pointers
Aug 30, 2013I came across the below code snippet in a project and was not sure how value of variable "response" is computed. Here as we can see, pic_data holds two one dimensional arrays but "response" access both the single dimensional array as two dimensional array.
Code:
#define MAX 100
#define MAXBUF 100
u32 response;
u32 index;
}
[code]....
C :: Pointers And Bi-dimensional Arrays
Feb 6, 2013I have a problem with a pointer and a bidimensional array. Here's the code:
typedef char t_board[5][4];
int i,j;
t_board *copy (t_board b) {
t_board *ptr;
ptr = (t_board *) malloc (sizeof(t_board));
[Code] ...
After this, I print new_board, and its ok; but the following code after the call to copy, crashes. Don't know why. if I remove the statement new_board = copy(some_board); , the code that follows runs ok.
C++ :: Arrays And Smart Pointers
Aug 3, 2014I'm writing quite a large program that needs to work with very large arrays (up to 100 million integers). It is necessary that i can access every point of the array directly (without running through the array) and that I use as little memory as possible. I first wrote the program with pointers that point to allocated heap memory. It works fine but now I wanted to use smart pointers instead (so I'm sure to have no memory leaks). Here's a simple visualization of my problem:
#include <iostream>
#include <memory>
using namespace std;
unique_ptr<int[]> upArray;
int main() {
int nArrayLength = 10;
[Code] ....
There are 2 things that do not work how I would like the to:
1. It wants me to assign the heap memory in one step: unique_ptr<int[]> upArray(new int[nArrayLength]); But I'd like to have the unique_ptr in my Class_Declaration before I know the array length and allocate the memory later.
2. *(upArray + i) = i;
cout << *(upArray + i);
Those lines don't work! How else can I do it.
C/C++ :: How To Use Pointers To Arrays In Function
Feb 25, 2015I am trying to use pointers to arrays in my function.
I can get the pointers to work outside of a function but I just can't figure out how to make them work in my function.jwhittle58, on 25 February 2015 - 06:06 PM, said:
I am trying to use pointers to arrays in my function. I can get the pointers to work outside of a function but I just can't figure out how to make them work in my function.
C :: Switch Case Character Scanf (also Includes Arrays)
Nov 10, 2014I'm trying to write a code that is read character user 'e' or ' ' space also numbers I mean a number 'e' or space 'e' a number 'e' or space so forth.But i get absurd numbers. The program shows me the added number. If '
' entered the taking numbers will stop(scanf will stop).
Example input:
e 1 8 7 2 3 6
or e 1 e 8 e 7 e 2 e 3 e 6
Code: #include <stdio.h>
#define MAX 10
void addq ( int *, int, int *, int * ) ;
void test();
[Code]....
C++ :: Passing / Returning Character And Integer Arrays With Functions
Jun 21, 2013Passing and returning character and integer arrays with functions using simple programs...use pointers if necessary
View 1 Replies View RelatedC :: Passing Arrays To Other Data Has Pointers?
May 7, 2013I am looking for an example of when passing arrays to other data that has pointers,
I understand the terms I would just like to see a small example of code that actually demonstrates this process.
C :: Functions Which Change Arrays Without Pointers?
Jan 17, 2014the book I learn from gave a task to write a program which gets a matrix , and we have to write a function that switches 2 columns or rows the user inputs .as far as I know a function can not change variables in the main function without using pointers .so , theoretically, can a function described here can be written without using pointers ? as far as I tried - it can not.
View 9 Replies View RelatedC++ :: Class With Pointers And Dynamic Arrays
Apr 25, 2014Class with Pointers and Dynamic Arrays
View 2 Replies View RelatedC++ :: Project Combining Arrays / Pointers And Structures
May 6, 2014Write a program that uses a record structure to store a Student Name, Student ID, Test Scores, Average Test Score, and Grade. The program should keep a list of test scores for a group of 6 students. The program should ask for the name, ID, and four test scores for each student. Then the average test score should be calculated and stored. The course grade should be based on the following scale:
Average Test Score Course Grade
------------------ ------------
90 - 100 A
80 - 89 B
70 - 79 C
60 - 69 D
59 or below F
A table should be displayed on the screen listing each student's name, ID, average test score, and course grade. Implement with functions.
My code runs but it isnt returning anything (readable/correct) and i have no clue why. This is what i have so far:
#include <iostream>
using namespace std;
const int columns = 4;
struct StuRec //user defined datatype {
int id[6];
char names[6][20];
[Code] .....
it compiles completely but at the end instead of showing the student name ID average score and class grade it shows.... [URL] .....
C/C++ :: Project Combining Arrays / Pointers And Structures
May 5, 2014Write a program that uses a record structure to store a Student Name, Student ID, Test Scores, Average Test Score, and Grade. The program should keep a list of test scores for a group of 6 students. The program should ask for the name, ID, and four test scores for each student. Then the average test score should be calculated and stored. The course grade should be based on the following scale:
Average Test Score Course Grade
------------------ ------------
90 - 100 A
80 - 89 B
70 - 79 C
60 - 69 D
59 or below F
A table should be displayed on the screen listing each student's name, ID, average test score, and course grade. Implement with functions.
My code runs but it isnt returning anything(readable/correct) and i have no clue why. This is what i have so far:
#include <iostream>
using namespace std;
const int columns = 4;
struct StuRec //user defined datatype {
int id[6];
char names[6][20];
int scores[6][4];
double avg[6];
char grade[6];
}; //semi-colon required
[Code] ...
C :: Sorting Arrays Of Pointers - Assigning Data To Gene
Feb 11, 2013Code:
typedef struct {
name_t name;
float beta[beta_num];
} gene_t;
[Code] ....
Is gene an array of address ? How come the compare function doesn't work ?
C++ :: How To Use Dynamic Memory Allocation And Pointers To Iterate Through The Arrays
Dec 21, 2014I need to use dynamic memory allocation and use pointers to iterate through the arrays that I have already in this program. I am lost, nothing I do works and where to use the pointers. I am just looking for a push in the right direction so I can finish this project and how I can implement pointers in my program.
#include <iostream>
#include <string>
#include <cstdlib>
#include <iomanip>
#include <stdio.h>
using namespace std;
[Code]...
C/C++ :: Why Do Void Function Pointers EXECUTE Arrays Of Hexcode
Dec 23, 2012I know how to use functions pointers in C and C++ and I know if you have something like
char buf[] = {
0x48, 0xb8, 0x3c, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x48, 0xbf, 0x02, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x0f, 0x05
};
((void (*) (void))buf)();
That this will execute those binary instructions in hexadecimal notation BUT WHY? I don't get why that works since that's an array of data not a function?
C++ :: Pointers And Arrays - Program To Display Sorted List And Average Of Scores With Appropriate Headings
Apr 22, 2014I am writing a class that dynamically allocates an array that holds a user-defined number of test scores (test scores go from 0 to 10 both included). Once all the test scores are entered and validated (values only between 0 and 10, both included), the array should be passed to a function that sorts them in ascending order. Another function should be called that calculates theaverage of all the scores.The main program should display the sorted list of scores and the average of the scores with appropriate headings.
View 6 Replies View RelatedC++ :: Multi-character Character Constant Error Message?
Sep 14, 2014I keep getting this warning message and I do not know how to fix it. Is it because I'm using char to instead of strings to replace all 't' with 'lp'?
#include<iostream>
#include<string>
#include <stdio.h>
using namespace std;
char * scanf(char * a) {
[code]....
