std::bsearch – cppreference.com

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definiert in Header `<cstdlib>`

`void* bsearch( const void* key, const void* ptr, size_t count, size_t size, int (comp)(const void, const void*) );`

Findet ein Element gleich Element, auf das key in einem Array, auf das ptr. Das Array enthält count Elemente der Größe size. Funktion, auf die comp ist für Objekt Vergleich herangezogen .

Original:

Finds an element equal to element pointed to by key in an array pointed to by ptr. The array contains count elements of size size. Function pointed to by comp is used for object comparison.

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Parameter

key	-	Zeiger auf das Element zu suchen Original: pointer to the element to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ptr	-	Zeiger auf das Array zu prüfen Original: pointer to the array to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
count	-	Zahl der Element in dem Array Original: number of element in the array The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
size	-	Größe der einzelnen Elemente in dem Array in Bytes Original: size of each element in the array in bytes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
comp	-	comparison function which returns a negative integer value if the first argument is less than the second, a positive integer value if the first argument is greater than the second and zero if the arguments are equal. `key` is passed as the first argument, an element from the array as the second. The signature of the comparison function should be equivalent to the following: `int cmp(const void a, const void b);` The function must not modify the objects passed to it.

Rückgabewert

Pointer auf die gefundene Element oder NULL sonst .

Original:

Pointer to the found element or NULL otherwise.

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Beispiel

#include <cstdlib>
#include <iostream>

int compare(const void *ap, const void *bp)
{
    const int *a = (int *) ap;
    const int *b = (int *) bp;
    return *a - *b;
}

int show_ptr(int *p) 
{
    if (p == NULL) {
        std::cout << "NULL\n";
    } else {
        std::cout << p1 << ' ' << *p1 << '\n';
    }
}

int main(int argc, char **argv)
{
    const int ARR_SIZE = 8;
    int arr[ARR_SIZE] = { 1, 2, 3, 4, 5, 6, 7, 8 };

    int key1 = 4;
    int *p1 = (int *) std::bsearch(&key1, arr, ARR_SIZE, sizeof(arr[0]), compare);

    int key2 = 9;
    int *p2 = (int *) std::bsearch(&key2, arr, ARR_SIZE, sizeof(arr[0]), compare);

    std::cout << "p1: ";
    show_ptr(p1);

    std::cout << "p2: ";
    show_ptr(p2);
}

Output:

p1: 0xbf9a4c88 4
p2: NULL

Siehe auch


qsort	Sortiert einen Bereich von Elementen mit nicht angegebenen Typ Original: sorts a range of elements with unspecified type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktion) [edit]

equal_range	Bandbreite der Rendite von Elementen übereinstimmenden eine bestimmte Taste Original: returns range of elements matching a specific key The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktions-Template) [edit]

C documentation for bsearch