logo
Tags down

shadow

Properties of a pointer to a zero length array


By : Tiff
Date : August 01 2020, 11:00 PM
it should still fix some issue Per recent CWG reflector discussion as a result of editorial issue 3178, new int[0] produces what is currently called a "past-the-end" pointer value.
It follows that a cannot be null, and a + 1 is undefined by [expr.add]/4.
code :


Share : facebook icon twitter icon

Go: how to convert unsafe.Pointer into pointer to array with unknown length?


By : Adam
Date : March 29 2020, 07:55 AM
will be helpful for those in need You first convert to an array of a type with a static length that can fit your data, then slice that array to the correct length and capacity.
code :
mapSlice := (*[1 << 30]float32)(unsafe.Pointer(&mmap[0]))[:n:n]

In C, how to sort an array of pointers where each pointer points to a variable-length array of int?


By : jacobh4535
Date : March 29 2020, 07:55 AM
should help you out As noted in the comments, the main answer is 'carefully'. The question itself doesn't say anything about sorting the content of the arrays. However, that is mentioned in one of the comments. Here's code that does the job, using the standard library function qsort() — twice. I extended the list of arrays a bit, and renamed arr6 to list to separate it from the other arrN arrays (and there is probably a better name for it than list — be my guest).
I called this qs79.c:
code :
/* SO 4335-0957 */
#include <stdio.h>
#include <stdlib.h>

void sort_arr(int num, int **list);
void print_arr(int num, int **list);

int main(void)
{
    int arr1[] = { 3, 9, 6, 7 };
    int arr2[] = { 2, 5, 5 };
    int arr3[] = { 0 };
    int arr4[] = { 1, 6 };
    int arr5[] = { 4, 5, 6, 2, 1 };
    int arr6[] = { 4, 2, 7, 1, 5 };
    int arr7[] = { 4, 2, 5, 1, 6 };
    int arr8[] = { 9, 12, 19, 18, 10, 28, 27, 15, 15, 27 };
    int arr9[] = { 4, 2, 5, 1, 5 };

    int *list[] = { arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9 };
    enum { NUM_LIST = sizeof(list) / sizeof(list[0]) };

    printf("Unsorted:\n");
    print_arr(NUM_LIST, list);
    sort_arr(NUM_LIST, list);
    printf("Sorted:\n");
    print_arr(NUM_LIST, list);
    return 0;
}

static int cmpintasc(const void *v1, const void *v2)
{
    int i1 = *(int *)v1;
    int i2 = *(int *)v2;
    return (i1 > i2) - (i1 < i2);
}

#if 0
static inline int min(int x, int y) { return (x < y) ? x : y; }

static int cmpintptrasc(const void *v1, const void *v2)
{
    int *i1 = *(int **)v1;
    int *i2 = *(int **)v2;
    int max = min(i1[0], i2[0]) + 1;
    for (int i = 1; i < max; i++)
    {
        if (i1[i] != i2[i])
            return (i1[i] > i2[i]) - (i1[i] < i2[i]);
    }
    return (i1[0] > i2[0]) - (i1[0] < i2[0]);
}
#endif

static int cmpintptrasc(const void *v1, const void *v2)
{
    int *i1 = *(int **)v1;
    int *i2 = *(int **)v2;
    return (i1[0] > i2[0]) - (i1[0] < i2[0]);
}

void sort_arr(int num, int **list)
{
    /* Sort each array in turn */
    for (int k = 0; k < num; k++)
        qsort(&list[k][1], list[k][0], sizeof(list[k][0]), cmpintasc);
    /* Sort the whole list */
    qsort(list, num, sizeof(list[0]), cmpintptrasc);
}

void print_arr(int num, int **list)
{
    for (int k = 0; k < num; k++)
    {
        printf("%d: [%d]  ", k, list[k][0]);
        for (int c = 1; c < (list[k][0] + 1); c++)
            printf("%d ", list[k][c]);
        printf("\n");
    }
}
Unsorted:
0: [3]  9 6 7 
1: [2]  5 5 
2: [0]  
3: [1]  6 
4: [4]  5 6 2 1 
5: [4]  2 7 1 5 
6: [4]  2 5 1 6 
7: [9]  12 19 18 10 28 27 15 15 27 
8: [4]  2 5 1 5 
Sorted:
0: [0]  
1: [1]  6 
2: [2]  5 5 
3: [3]  6 7 9 
4: [4]  1 2 5 5 
5: [4]  1 2 5 6 
6: [4]  1 2 5 7 
7: [4]  1 2 5 6 
8: [9]  10 12 15 15 18 19 27 27 28 
Unsorted:
0: [3]  9 6 7 
1: [2]  5 5 
2: [0]  
3: [1]  6 
4: [4]  5 6 2 1 
5: [4]  2 7 1 5 
6: [4]  2 5 1 6 
7: [9]  12 19 18 10 28 27 15 15 27 
8: [4]  2 5 1 5 
Sorted:
0: [0]  
1: [4]  1 2 5 5 
2: [4]  1 2 5 6 
3: [4]  1 2 5 6 
4: [4]  1 2 5 7 
5: [2]  5 5 
6: [1]  6 
7: [3]  6 7 9 
8: [9]  10 12 15 15 18 19 27 27 28 

Need to implement a recursive mergesort code in C using array pointer, its length and a workspace array for the merge fu


By : user1570776
Date : March 29 2020, 07:55 AM
To fix this issue The merging phase in function merge_sort iterates on both halves in parallel, taking the smallest element from either side at a time:
code :
void merge_sort(int *a, int *w, int n) {
    if (n < 2) {
        return;
    } else {
        int i, j, k;
        int n1 = n / 2;
        int *b = a + n1;
        int n2 = n - n1;

        /* sort the left half */
        merge_sort(a, w, n1);
        /* sort the right half */
        merge_sort(b, w, n2);

        /* merge the halves into w */
        for (i = j = k = 0; i < n1 && j < n2;) {
            if (a[i] <= b[j]) {
                /* get smallest value from a */
                w[k++] = a[i++];
            } else {
                /* get smallest value from b */
                w[k++] = b[j++];
            }
        }
        /* copy remaining elements from a */
        while (i < n1) {
            w[k++] = a[i++];
        }
        /* copy remaining elements from b */
        while (j < n2) {
            w[k++] = b[j++];
        }
        /* copy sorted elements back to a */
        for (i = 0; i < n; i++) {
            a[i] = w[i];
        }
    } 
}
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define ARRAY_MAX 100000

int main(void) {
    int my_array[ARRAY_MAX];
    int work_space[ARRAY_MAX];
    int i, count;
    clock_t start, end;

    count = 0;
    while (count < ARRAY_MAX && scanf("%d", &my_array[count]) == 1) {
        count += 1;
    }

    start = clock();
    merge_sort(my_array, workspace, count);
    end = clock();

    for (i = 0; i < count; i++) {
        printf("%d\n", my_array[i]);
    }

    fprintf(stderr,"%d %f\n", count, (end - start) / (double)CLOCKS_PER_SEC);

    return EXIT_SUCCESS;
}

Is it possible to find the length of an array if I have only the pointer to the first array element taking into account


By : Tapas
Date : March 29 2020, 07:55 AM
To fix the issue you can do No it's not possible. This is one of the many, many reasons that you should normally use std::vector instead of arrays.
Vectors are actually easier, safer, more powerful and more intuitive than arrays. The sooner you learn how to use them the better.

Why does the length of array shows zero when we define a set of array properties using character value instead of numeri


By : dustfree
Date : March 29 2020, 07:55 AM
will be helpful for those in need As you can check in here:
code :
var array = [];

array[0] = 1;
// Length = 1
console.log(array.length);

array["five"] = 5;
// Length still = 1
console.log(array.length);

array[1] = 1;
// Length now is = 2
console.log(array.length);

array[4] = 1;
// Length now is = 5, because you are adding an element to the position 4
console.log(array.length);
console.log(array);
Related Posts Related Posts :
  • Using disabledDate in Antd Datepicker in table
  • iterator .end() from std::list returns "0xcdcdcdcdcdcdcdcd" but .begin() as expected
  • how to convert HAC flexible query to DAO query
  • Cannot refresh UI if update in ItemView
  • How to make a function to use dict keys as variables to a class?
  • Best approach to remove cassandra-topology.properties file in running cluster nodes
  • plsql store procedure loop compare value
  • Replace values in XML file with values of a vector
  • Convert old SQL Database in compatibility mode
  • Sum same property object by group
  • What do you do about the JLabel classes? It says, "JLabel not a statement" for the error
  • Is std::sqrt the same as sqrt in C++
  • Iterate through std::initializer_list
  • Why does the overidden run method in java.lang.Thread produce a bizarre output?
  • Typescript: type one parameter based on the other
  • How to add a CSS to this JavaScript or HTML on click buttons?
  • Is it OK to inherit an empty Interface?
  • Functional Interface call for a new Instance
  • Microsoft Bot Framework: Smilies in MS Teams
  • changing background image of div using javascript
  • How to convert two arrays of strings to the array of objects like key and value with particular keys in javascript?
  • What is the fastest way to find if a column has at least one NULL value in ORACLE database?
  • Rename headers - 'list' object is not callable
  • Codeblocks c++ code doesn't run in VS 19 (vector subscript out of range)
  • Passing res.send value from node.js backend to react.js
  • Vim shortcuts to select and copy the current line without the next line
  • Is it possible to pass data from an angular7 component or service to index.html file?
  • When I tried to add ArrayList into ArrayList second ArrayList is repeating
  • If I implement IEquatable<T>, will I lose the option to compare by reference?
  • Authorize with both ASP.NET core MVC/Razor site AND a WebAPI
  • Compare two version of zip file and find which file has been modified within that zip
  • Dynamically generated href won't show properly
  • Best way to saving completed progress in table?
  • Does UIWindow function not work in Xcode11.3?
  • TypeError: __init__() takes 2 positional arguments but 6 were given
  • Converting string (with timezone) to datetime in python
  • How to overwrite the theme in shopify
  • Get the no of consecutive days a Field value is Stale
  • How to keep track of previous value of variable in swift?
  • Can't get result when running the query from Spring Data Jpa
  • If Condition Simplification
  • Python list generation from two strings
  • How to find distinct records in vespa.ai?
  • Why erase on std::vector promote iterator
  • How to use data to set other data in Vue.js
  • Azure AD does not return groups on claims
  • ASP Net Core Web API: Client side GroupBy is not supported
  • How to correct TypeError: Unicode-objects must be encoded before hashing with ReportLab
  • how to destroy an object in C++
  • How to do pagination using groupby in vespa.ai?
  • How can I print the longest word from a user defined list?
  • C# I have a DLL file and I need to make a class that inherits from a class that's in the DLL file?
  • Can someone explain to me why my factorial recursion code can't be compiled
  • Pass a PHP variable to a JS variable
  • Showing messages based on scroll position
  • How to copy cells via vba macro without getting subscript out of range
  • Replace substring in shell script
  • enabling authentication in ignite
  • Swipe to delete rows with multi section in tableview?
  • [BootstrapVue warn]: popover - Unable to find target element in document
  • shadow
    Privacy Policy - Terms - Contact Us © voile276.org