Section 1
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semantics
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Section 1
(50 cards)
semantics
meaning behind the language
assembler
a program that takes the source code of an assembly written program and turns into object code. There are different assemblers for different processors.
C language
static, weak, and compiled to machine code low-level control, efficiency Good for writing Operating system
Why can't compilers have garbage collections?
That'd defeat the whole purpose of a compiler language. The main reason why you'd use compiler language is for their efficiency with memory and speed. If a garbage collection was programmed into the language then it'd have unnecessary overhead defeating the whole reason why you'd want to work with compiler language in the first place.
Low-level
The advantage of low level languages are 1) precise control 2) efficiency Ex. Assembly
imperative paradigm
The paradigm that says to allow modification of states outside a function. To have a side effect.
OS's Kernel
computer program that manages input/output requests from software, and translates them into data processing instructions for the central processing unit and other electronic components of a computer.
Garbage collection(automatic memory management)
The interpreter auto allocates heap memory when the programmers use it or when the programmer doesn't need it anymore.
C++
an (almost) superset of C C with features for OOP Good for commerical applications
Strong typing
allows the programmer to manipulate a piece of data only with operations defined for that data's type. Because arbitrarily manipulating bytes may cause error, you restrict programmers to what the programming language defines nothing more.
Why is the assembler/compilation phase and linker phase separate?
It is because it saves time when a code needs to change. Rather than having to assemble/compile and link all the source code all at once, you can just assemble or compile the source code that needs to be changed and linked with the other object codes that has already been assembled or compiled.
Dynamic Linking
The ability to link code(shared libraries) from other files to the executable during runtime. .so(Linux) .dll(Windows)
source code
the text code that is human readable
System call
how a program requests a service from an operating system's kernel.
syntax
arrangement of the language
Procedural
action-centered design. Lines after lines of codes with not much modularization
Paradigm
a style of solving program problems
linker
a program that links together multiple object codes that was assembled or complied from a source code. The linker is necessary to turn a program into an executable.
Function signature
a function's name and its number/types/order of parameters. The return type does not count.
Compilers
program that is used to translate from high level languages to machine code
Type error
a bug that occurs in the program when you call upon the wrong type of data. Ex. x = true if(x>10) { // code } During the runtime, the interpreter or the compiler will say Type Error Exception because you can not logically compare a Boolean type with a integer. This type of program only occurs in dynamic typing language. Static typed languages detect this before run time.
Interpration
Reads source code and turns it into action. It does what the source code says line by line unlike compilation which translates all code into machine code before turning it into action.
Terminals
Electronic keyboards and screens
Memory leak
a bug in which the program allocates a chunk of heap memory but neglects to give the chunk back to the OS when it's no longer needed. Memory leaks can make programs use up all the address space the OS is willing to give.
Dynamic Typing
a programming language that does not declare the types of variables, parameters, and functions. It checks the operands of operations at RUNTIME. More flexible, especially when using collections
assembly language(assembly)
A language that is used to represent the bytes for manipulation. These languages are processor specific.
Why use dynamic linking and shared libraries?
Memory usage. When multiple programs are running at the same time, it saves memory to run only one copy of that code. When multiple processes use the same library, the libraries include in each process's address space and their virtual memory, but the actual code is in one physical memory.
Popularity of programming paradism
Most popular 1) Object Oriented/Imperative(Most languages of today) 2) Procedural/Imperative 3) Object Oriented/functional 4) Procedural/ Functional Least popular
Weak typing
allows the programmer to manipulate bytes of data in any arbitrary way desired Ex. Assembly languages Sure programmers might make mistakes;however, sometimes programmers want the flexibility of control cover the bytes.
Static Typing
Exact opposite of dynamic. This type of programming language makes sure that you declare the types of variables, parameters, and functions. The types of operands, arguments, and assigned values are checked before execution. Ensures that type errors does not occur.
Compilation and Interpretation hybrid
It takes source code and compiles it into bytecode which is interpreted by the JVM. The reason why this hybrid exists is because they wanted to make a language that had both the benefits of compilation and interpretation Ex. Java
High-level Lanuage
The advantage of high level languages are 1) expressiveness 2) portability across multiple processors Ex. C, C++, Java
Machine Code
code that only computers can understand
functional paradigm
The paradigm that says you are NOT allowed to modify anything outside the function when using the function. All and everything that happens in the function stays in the function without a side effect.
Polymorphism(method overloading in static languages)
ability of operations or functions to accept the varied number and.or types of inputs and possibly changes behavior for each and every varied inputs Ex. the print method print("Hello") print(100) print(false)
tool
any sort of program to create software 1) compiler 2) linker 3) interpreter 4) text editor(Notepad++) 5) debugger ---> program tool that helps programmer tract down bugs by executing code step by step while reporting what's happening in program memory 6) profiler ---> a tool that helps are programmers optimize their code by measuring the performance of code 7) version control ----> a snapshot of code of a project that can be stored in repositories for programmers to go back. Version control also helps programmers organize their code in repositories instead of having the mess of organizing it on your computer. 8)IDE(Integrated Developer Environment)
Assembly vs Compilation
To assemble, Each line of source code corresponds with one instruction. Each line of code becomes one instruction resulting in program. To compile, Each line of source code does NOT correspond with one instruction, but rather multiple instructions.
libraries
body of pre-existing code. We use libraries for common functionality. Most languages have something called "standard libraries"
Why would you mix Assembly and C?
In all high level language, there is no way to invoke a "system call". Only Assembly languages can invoke a system call.
Can you link and run programs that are written in Assembly and C?
Yes, they both produce object files. foo.asm ----> foo.o bar.c -----> bar.o
Heap
part of the program memory where you can store anything else you want other than local variables. Programmers explicitly must ask the OS to allocate heap memory. When finished with heap memory, the programmer must manually de-allocate the heap memory or that will cause memory leak.
Can interpreters have memory leak despite having a garbage collector?
Yes. The auto garbage collection only occurs when a data is de-referenced to any existing variable. If a programmer forgets to de-reference a variable, the garbage collection will not activate.
What is Address space(program memory) made of?
1) text(code) ---> Auto allocated by OS 2) call stack(local variables) ---> Auto allocated by OS 3) heap(Everything else) ---> manually manage by programmer
Compilation
the translation from high level language to machine code
Object-oriented
data-centered design. Codes of lines are categorized by objects. All objects have attributes and behaviors. These attributes and behaviors are encapsulated in an object and they communicate with other objects by sending a message .
What does a interpreter need to work?
1) Arithmetic 2) Variables 3) Control flow 4) Functions
Compilation vs Interpretation
Compilation 1) Faster and efficient Interpretation 2) Portability
JIT(Just In Time)
JIT is used with VM which has the ability to compile bytecode to machine codes when some part of a bytecode is being used often.
Interpreter
program used to read source code to produce action line by line. Linker is not necessary for Interpreter since it does the linking itself between 2 or more source code files.
Hex-editior
a program that allows the editing of bytes in hex form
Section 2
(23 cards)