Sequential search in an array P11725

Write a function that tells if the integer number @x@ is present in the vector of integer numbers @v@.

In order to compare the efficiency of your solution against the efficiency of the solution of the Judge, start searching for @x@ from the lowest positions.

Interface

bool exists(int x, const vector<int>& v);

int exists(int x, const int v[], int vsize);

public static boolean exists(int x, int[] v);

exists(x, v)  # returns bool

exists(x: int, v: list) -> bool

Observation

You only need to submit the required procedure; your main program will be ignored.