Building a function that calls on an array and finds its maximum

Can somebody help/ give me an example of a function that would find the maximum of an array. Any help would be appreciated.

[David Hill]

x=[4 8 34 23 98 31];
y=max(x);

[Walter Roberson]

(That could would find the maximum of a scalar or vector, not of an array with 2 or more dimensions.)