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# gmp_nextprime

(PHP 5 >= 5.2.0, PHP 7)

gmp_nextprimeFind next prime number

### Descrierea

GMP gmp_nextprime ( int `\$a` )

Find next prime number

### Parametri

`a`

Un număr GMP sub formă de resource în PHP 5.5 și anterior, un obiect GMP în PHP 5.6 și ultrior, su un șir de caractere numeric atunci când acesta poate fi convertit într-un număr.

### Valorile întoarse

Return the next prime number greater than `a`, as a GMP number.

### Exemple

Example #1 gmp_nextprime() example

``` <?php\$prime1 = gmp_nextprime(10); // next prime number greater than 10\$prime2 = gmp_nextprime(-1000); // next prime number greater than -1000echo gmp_strval(\$prime1) . "\n";echo gmp_strval(\$prime2) . "\n";?> ```

Exemplul de mai sus va afișa:

```11
-997
```

### Note

Notă:

This function uses a probabilistic algorithm to identify primes and chances to get a composite number are extremely small.

### User Contributed Notes 3 notes

IceMetalPunk at gmail dot com
1 year ago
``` Negative numbers N always have at least four factors: N*1=N and abs(N)*-1=N. Therefore, even if "natural number" weren't in the definition of a prime (which it is), no negative number would ever qualify. Therefore, the next-largest prime number to any negative number is always 2. ```
Anonymous
2 years ago
``` It seems gmp_nextprime on negative numbers always returns 2. ```
Tommy Lynge Jrgensen
1 year ago
``` Prime numbers are positive, non-zero numbers that have exactly two factors. No more, no less. So testing negative numbers doesn't really make any sense. ```