Computer Science A: Quick Reference Guide

(From: http://apcentral.collegeboard.com/members/article/1,3046,151-165-0-21170,00.html)

class java.lang.Object
// all classes inherit and may override these methods

• boolean equals(Object other)
• String toString()

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interface java.lang.Comparable

• int compareTo(Object other)
  // return value < 0 if this is less than other
  // return value = 0 if this is equal to other
  // return value > 0 if this is greater than other

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class java.lang.Integer implements java.lang.Comparable

• Integer(int value)
  // constructor
• int intValue()

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class java.lang.Double implements java.lang.Comparable

• Double(double value)
  // constructor
• double doubleValue()

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class java.lang.String implements java.lang.Comparable

• int length()
• String substring(int from, int to)
  // returns the substring beginning at from
  // and ending at to-1
• String substring(int from)
  // returns substring(from, length())
• int indexOf(String s)
  // returns the index of the first occurrence of s;
  // returns -1 if not found

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class java.lang.Math

• static int abs(int x)
• static double abs(double x)
• static double pow(double base, double exponent)
• static double sqrt(double x)

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class java.util.Random

• int nextInt(int n)
  // returns an integer in the range from 0 to n-1 inclusive
• double nextDouble()
  // returns a double in the range [0.0, 1.0)

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class java.util.ArrayList

• int size()
• boolean add(Object x)
  // appends x to the end of list; returns true
• Object get(int index)
  // returns the element at the specified position
• Object set(int index, Object x)
  // replaces the element at index with x
  // returns the element formerly at the specified position
• void add(int index, Object x)
  // inserts x at position index, sliding elements
  // at position index and higher to the right
  // (adds 1 to their indices) and adjusts size
• Object remove(int index)
  // removes element from position index, sliding elements
  // at position index + 1 and higher to the left
  // (subtracts 1 from their indices) and adjusts size
  // returns the element formerly at the specified position