Code:
int arr[10];
int* p = arr;
int (*p2)[10] = &arr;
So, pointer p is a pointer to an array, I can use it to access elements of arr as in *(p+5).
Pointer p2 is a pointer to an array of ten integers. What is it for, how can I use it to access elements of arr?
I want to access the elements of my array dynamically. So far I've only figured out how to do this manually. if I tried it like this my code would work but there should be a better way right?
View 10 Replies View RelatedI am trying to retrieve the elements in an array to print them. I am pretty sure I have everything right, but it is not working. There are 5 values in the array {3, 4, 10, 5, 6}, but the first two elements (supposed to be 3,4) are coming out a 0,-2654238590. The last three elements are coming out correct.
void addDynArr(DynArr *v, TYPE val) {
/* FIXME: You will write this function */
assert(v != 0);
//resize if necessary
if(v->size >= v->capacity)
[Code] ....
I've been working for some number of days on this code to take information about movies from both a file and the user, store the infos in an array of structs, and at the end, write all the info out to a file. I'm having some problems with an error message reading:
"prog.c:102:11: error: subscripted value is neither array nor pointer nor vector"
this error occurs in many lines (which I will label specifically below -- they are everywhere where I am trying to access/modify an individual element of a struct element of the array).
A few examples of where I am having the problems are lines:
39, 52-55, 70, 72, and 86 (and more of the same exact variety).
I am obviously rather systematically doing something wrong, but I am quite certain all of these are the exact same mistakes.
I pull up also 2 or 3 other errors, but I don't think they are related and should be able to fix them quickly once I work out this conundrum.
#include <string.h>
#include<stdlib.h>
#include <stdio.h>
int moviecount =0;
typedef struct{
int year;
[Code] .....
I am writing a C program to access a string into an array from a pointer array in Visual Studio 2010. Program is given below:-
Code:
#include <stdio.h>
#include <string.h>
void main() {
char data_a[6],data_b[6]="ABcde",*ptr;
ptr=&data_b[0];
data_a[0]=*ptr;
printf("%s",a);
}
I am getting some junk character first and then my actual data on console window. I want to where I am getting wrong and how to resolve it.
I'm confused about accessing elements from arrays. Supposed I have an array of pointers to char:
char *names = { "John", "Rose", "Steven" };
To access one of the strings, should I use names[ 0 ][ i ], where i is an index in the set ( 0, 1, 2 ), or should I use names[ i ]? I would think it would be the first option, because this array has 1 dimension that contains others arrays, right?
so lets assume i have a nested vector in a set or vice versa o in a more general form a container in a container example...
Code:
std::set<vector<int> > my_tuple;
How do i access individual elements of lets say the first vector in the set! Or the last element in the 3rd vector?
I have a pointer to a vector of objects, each object has an array and a couple of strings. how to access the data in the objects via the pointer.
Best tree::chooseSplit(vector <pgm> *ptr)
{
Best splits;
cout<<ptr[1].filePath; //not working!!!
}
filepath is a string in the pgm object. i also need to be able to access elements in an array that also exists in pgm.
"
#include <stdio.h>
struct datastructure {
char character;
};
void function(struct datastructure** ptr);
[Code] ....
These codes give these errors:
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
These errors are related to
"
*ptr->character='a';
printf("Ptr: %c",*ptr->character);
"
I want to access "character" data inside the structure "trial" by a pointer to pointer "ptr" inside function "function",but I couldn't find a way to do this.
i had a structure as follows:
struct a{
int x;
struct b{
int y;
b *next;
}b;
};
when i try to access as follows:
struct a *a;
a->b=a->b->next;
i got the following error: base operand of ‘->’ has non-pointer type
"Write a declaration for a function that takes two int parameters and returns an int, and declare a vector whose elements have this function pointer type."
View 9 Replies View RelatedWrite a program that reads in the names and the ages of ten people. Store these data in two arrays (make sure that the entered names are not longer than the array size you choose). Then produce a table of ten lines, with each line giving the name and age of a person along with the (positive or negative) deviation of that person's age from the average age. The code I wrote to fill in the arrays looks as follows
Code:
#include<stdlib.h>
#include<stdio.h>
int main()
{ // begin main()
// array length
[Code]....
When I compile it, it gives me warnings that few of the variables I declared aren't used, but that is not affecting the program at all. When I run the program, it allows me to pass the names and ages into the arrays, but when it comes to displaying them, I'm getting a 'Segmentation fault'. I used very similar code in Java to write the program, and it worked fine so what is the problem with C then?
I was wondering if it was possible to access data from an array inside a threaded function after it has finished executing?
Take this example:
Code:
#include <iostream>
#include <boost/thread.hpp>
using namespace std;
[Code]....
After workerFunc has finished, how could I access the array arr? Is there any way to get (3,4,5,6,7) back into main()?
I'm okay with 2-dimensional arrays, but when I get to 3 or more, I can't seem to wrap my head around how to assign and/or pull values from specific parts.
To give an example, let's take the following example:
We know that a player can take up to 5 total quests, and each quest can have a max of 5 tasks.
Let's assume I have the following multi-dimensional array holding all of a players quest data:
quests[0] = 78;// Store the questID
quests[0][0] = 3945;// Store the 1st creature ID
quests[0][1] = 2230;// Store the 2nd creature ID
quests[0][2] = 3045;// Store the 3rd creature ID
quests[0][0][0] = 2;// Store how many needed of the 1st creature
quests[0][1][0] = 5;// Store how many needed of the 2nd creature
quests[0][2][0] = 13;// Store how many needed of the 3rd creature
As we know, the above code can't be done. How do I assign certain values to each specific dimension?
I have a contiguous sequence of section headers in a file (all the data in the file is stored in void * data), where each section header is the same size and has the same fields in the same order. So it's laid out like an array.
I have to:
- Use an offset value and the number of section headers variables to identify the location and length of the section header table (these are hdr.offset and hdr.length respectively).
- The offset value shows the distance between the start of the file and the start of the first section header (so I need a pointer to the start of the first section header)
- Apply a typecast to location of the section header table to process it as an array of section headers.
Here is what I have done, but I am getting a segmentation fault. What am I doing wrong? How do I fix this?
typedef struct {
unsigned int name;
unsigned int type;
} SectionHeader;
[Code] ....
Write 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
Write a function that takes an array and returns true if all the elements in the array are positive, otherwise, it returns false.
View 6 Replies View RelatedI am having problem in writing the code for the problem "To assign the elements of 1-D integer array into 2-D array of integers such as if the array is 1,2,3,4,5,6 The resultant 2-D array should be like :
1 0 0 0 0 0
1 2 0 0 0 0
1 2 3 0 0 0
1 2 3 4 0 0
1 2 3 4 5 0
1 2 3 4 5 6
"
i have been fiddling with pointers but I don't understand how the proper syntax is written when I want to acces an element of an array through a pointer to a pointer...The code is all mostly just random bs for learning purposes. I marked the problem "// THIS LINE"
Code:
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DATA 100
int find_average(char *iden, ...) {
[Code]...
This is a sample program that declares a Matrix as a structure with an array as a pointer to a pointer. The following program is supposed to store a matrix in the structure "_Matrix" and later print the matrix just entered but it fails giving me a "segmentation fault". The sample code is given below
Code:
#include <stdio.h>
#include <stdlib.h>
struct _Matrix {
int row_size;
int col_size;
int **mat;
[Code] ......
I have just started learning C language, I have read that array name is the pointer to the first element of array.
So,technically both a and a[0] should have different memory address and a should hold address of a[0],
But when I declare an array and print the address:
int a[5]={2,4,6,8,10};
printf("The address of a and a[0] are &d and %d",&a,&a[0]);
Output is: The address of a and a[0] are 2358832 and 2358832
Why I am getting the same result, shouldn't I be getting different memory address for both a and a[0].
I've a file that looks like this:
84484-37.96-Castor, Kathy
39050-69.68-Chandler, Ben
26183-70.84-Costello, Jerry
I have successfully read each element the id, grade and name into 3 separate array. Now i need to add a new student with an id and grade
How do i do this?
This is what I have.
int addStudent( int Iarray[], double dArray[], string sArray[], int newID,
double newGrade, string newName, int size ) {
char ready;
int index;
cout << endl;
cout << "Enter new student ID number : ";
[Code]...
I have a question regarding the elements of an array. Suppose I have a 3 by 3 string array (char x[3][4] ) , and I initialize all the elements to x's , the array would then look like this :
xxx
xxx
xxx
I'm curious if there will be a value if I try to access and element outside the array. As I have to write a code to determine if I have reached the end of an array. The only way I can think of is to border the entire array with o's , making it look like this :
ooooo
oxxxo
oxxxo
oxxxo
ooooo
Is there any other way to do this?
I have the following code :
Code:
#ifndef TDYNAMICARRAY_H
#define TDYNAMICARRAY_H
namespace Massive {
template<class T>
T **AllocateDynamic2DArray(int nRows,int nCols)
[Code] .....
I wish to know how to traverse or loop through a dynamic 2D array using pointer to pointer as returned by the code above. Like I would in a static T[20][20] 2D array.
Trying to concatenate the 1st and 2nd element from an array of chars. Then this to be used as a hex value.
so for example
specs[0]='f'
specs[1]='4'
concatenate_value=0xf4
Write the definition of a function reverse , whose first parameter is an array of integers and whose second parameter is the number of elements in thearray . The function reverses the elements of the array . The function does not return a value .
Code:
void reverse(int a[], int num) {
for ( int i=0; i <= num/2 ; i++){
int temp = a[i];
a[i] = a[num-i-1];
a[num-i-1] = temp;
} }
This is supposed to be the answer but I'm not quite sure why this is. I understand everything up until the actual loop. For one, shouldn't "int i" be declared outside the loop (I thought perhaps this was an error in the solutions)?
The main thing that I do not understand is the conditional statement.
Code: i<=num/2;
I don't understand why the "num/2" is necessary here. Also I can't really remember but is there a command that actually reverses an array?