std::bsearch - cppreference.com

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Definido no cabeçalho `<cstdlib>`

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

Localiza um elemento igual ao elemento apontado por key em uma matriz apontada por ptr. A matriz contém elementos count de size tamanho. Função apontada pelo comp é usado para comparação de objetos.

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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Parâmetros

key	-	ponteiro para o elemento para pesquisar 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	-	ponteiro para a matriz para examinar 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	-	número de elementos na matriz 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	-	tamanho de cada elemento na matriz em 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.

Valor de retorno

Ponteiro para o elemento encontrado ou NULL contrário.

Original:

Pointer to the found element or NULL otherwise.

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Exemplo

#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);
}

Saída:

p1: 0xbf9a4c88 4
p2: NULL

Veja também


qsort	Classifica um intervalo de elementos de tipo não especificado 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. (função) [edit]

equal_range	retorna a escala de elementos que combinam com uma tecla específica 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. (modelo de função) [edit]

Documentação C para bsearch