diff --git a/_sources/Unit1-Getting-Started/survey.rst b/_sources/Unit1-Getting-Started/survey.rst index a9fb5e5c..f5b6c997 100644 --- a/_sources/Unit1-Getting-Started/survey.rst +++ b/_sources/Unit1-Getting-Started/survey.rst @@ -4,7 +4,7 @@ Survey Sisters Rise Up =============== -Sisters Rise Up is a research study at the University of Michigan that is trying to determine ways to help women of color (Black, Latinx, and/or Native American) who are taking Advanced Placement Computer Science A (CSA) succeed in the course and on the exam. It offers free remote one-hour help sessions twice a week which are led by undergraduate students at the University of Michigan. If you are interested in Sisters Rise Up please fill out the form at https://bit.ly/2QXPri1 with your parent or guardian's contact information. +Sisters Rise Up is a research study at the University of Michigan that is trying to determine ways to help women of color (Black, Latinx, and/or Native American) who are taking Advanced Placement Computer Science A (CSA) succeed in the course and on the exam. It offers free remote one-hour help sessions twice a week which are led by undergraduate students at the University of Michigan. If you are interested in Sisters Rise Up please fill out the form at https://tinyurl.com/55z7tyb9 with your parent or guardian's contact information. Sisters Rise Up will cover concepts on the AP CS exams, answer your questions, and introduce you to role models. Students who have been in Sisters Rise Up value meeting other women like them in computing, getting their questions answered, going deeper into topics, and learning about opportunities in computing. diff --git a/_sources/Unit1-Getting-Started/topic-1-3-variables.rst b/_sources/Unit1-Getting-Started/topic-1-3-variables.rst index 7b29aa6d..dddb68e0 100644 --- a/_sources/Unit1-Getting-Started/topic-1-3-variables.rst +++ b/_sources/Unit1-Getting-Started/topic-1-3-variables.rst @@ -54,20 +54,31 @@ Data Types There are two types of variables in Java: **primitive variables** that hold primitive types and **object or reference variables** that hold a reference to an object of a class. A reference is a way to find the object (like a UPS tracking number helps you find your package). The primitive types on the Advanced Placement Computer Science A exam are: - - int - which store integers (numbers like 3, -76, 20393) - - - double - which store floating point numbers (decimal numbers like 6.3 -0.9, and 60293.93032) - - - boolean - which store Boolean values (either true or false). - -**String** is one of the object types on the exam and is the name of a class in Java. A *string* object has a sequence of characters enclosed in a pair of double quotes - like "Hello". You will learn more about ``String`` objects in Unit 2. - - -.. note:: - - Some languages use 0 to represent false and 1 to represent true, but Java uses the keywords ``true`` and ``false`` in boolean variables. - -A type is a set of values (a domain) and a set of operations on them. For example, you can do addition with int's and double's but not with booleans and Strings. +- ``int`` which can represent integers, i.e. numbers with no fractional part + such as 3, 0, -76, and 20393. + +- ``double`` which can represent non-integer numbers like 6.3 -0.9, and + 60293.93032. Computer people call these “floating point” numbers because the + decimal point “floats” relative to the magnitude of the number, similar to the + way it does in scientific notation like :math:`6.5 ✕ 10^8`. The name + ``double`` comes from the fact that ``double``\s are represented using 64 + bits, double the 32 bits used for the type ``float`` which used to be the + normal size floating point number when most computers did math in units of + 32-bits. (``float`` is rarely used these days and is not part of the AP + curriculum.) + +- ``boolean`` which can represent only two values: ``true`` and ``false``. (The + data type is named for `George Boole + `_, a 19th century English + mathematician who invented Boolean algebra, a system for dealing with + statements made up of only true and false values.) + +``String`` is one of the object types on the exam and is the name of a class in +Java. A ``String`` is written in a Java program as a sequence of characters +enclosed in a pair of double quotes - like ``"Hello"``. You will learn more +about ``String`` objects in Unit 2. + +A type is a set of values (a domain) and a set of operations on them. For example, you can do addition operations with ``int``\s and ``double``\s but not with ``boolean``\s and ``String``\s. |Exercise| **Check your understanding** diff --git a/_sources/index.rst b/_sources/index.rst index 5b6ef60c..eec39bda 100644 --- a/_sources/index.rst +++ b/_sources/index.rst @@ -23,7 +23,7 @@ ATTENTION high school women of color taking AP CSA or CSP: if you identify as fe .. ATTENTION high school seniors: apply for the https://www.amazonfutureengineer.com/scholarships until Dec. 15th for college scholarships and Amazon summer internships for students with financial need. -Apply for the ACM Cutler-Bell Scholarship https://csteachers.org/awards/cutlerbell/ until Jan. 19th. +.. Apply for the ACM Cutler-Bell Scholarship https://csteachers.org/awards/cutlerbell/ until Jan. 19th. **CSAwesome Units:**