How do I create a uml diagram for this code?

[glamiex]

I need to create a UML class diagram for this code

private:
GradedActivity *grades[NUM_GRADES];

public:
void setLab(GradedActivity *activity)
{ grades[LAB] = activity; }

[DeXecipher]

http://lmgtfy.com/?q=uml+diagramming+tool