Lecture 01 Course Introduction
Computer Science is no more about computers than astronomy is about telescopes.
- Introduction to Programing
- Managing Complexity: Mastering Abstraction; Programing Paradigms
This is a challenging course that will demand a lot from you.
But this will also be a fruitful course that will bring a lot to you.
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Ask for help if you are stuck and make a good effort on all of the homework.
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Do not share code.
Expressions
Description
An expression describes a computation and evaluates to a value.
Types of expressions
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Primitive Expressions:
2(numbers);"hello"(strings);add(names) -
Arithmetic Expressions:
1 + 2;15 // 3 -
Call Expressions:
add(3, 4);max(add(2, 3), 5*min(-1, 4))
Evaluating call expressions
- Evaluate
- evaluate the operator subexpression
- evaluate each operand subexpression
- Apply
- apply the value of the operator subexpression to the values of the operand subexpression
Values
Description
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Programs manipulate values
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Values represent different types of data
Types of data
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Integers:
2;44;-3 -
Strings:
"hello";"cs61a" -
Floats:
3.14;4.5;-2.0 -
Booleans:
True;False
Expressions evaluate to values in one or more steps