Ch 2: Overview Of C

Front 1

Funktion

Back 1

En samling programsatser som "gör något"

Ett C-program börjar med main-funktionen, vilken kallas då exekvering startas.

Front 2

getchar()

Back 2

Väntar på att användaren ska trycka på Enter

Front 3

return 0;

Back 3

Returnerar ett värde till OS.

0 betyder att programmet lyckats

Front 4

Preprocessor directives

Back 4

A C program line beginning with # that provides an instruction to the preprocessor

Front 5

Preprocessor

Back 5

A system program that modifies a C program prior to its compilation

Front 6

Library

Back 6

A collection of useful functions and symbols that may be accessed by a program.

Not defined directly by C

Front 7

#include

Back 7

Gives a program access to a library

Front 8

#define

Back 8

Associates a constant macro with a constant value

Front 9

Constant macro

Back 9

A name that is replaced by a particular constant value before the program is sent to the compiler

Front 10

Main function

Back 10

Every C program has a main function

The body of the function is enclosed in braces

Front 11

Declarations

Back 11

The part of a program that tells the compiler the names of memory cells in a program

Front 12

Executable statements

Back 12

Program lines that are translated into machine language and later executed

Front 13

Reserved word

Back 13

A word that has special meaning in C

Front 14

Standard identifiers

Back 14

Have special meaning, such as printf and scanf.

Can be redefined, but cannot then be used for its original purpose.

Front 15

User-defined identifiers

Back 15

Can consist of letters, digits and underscores

Cannot begin with a digit

A reserved word cannot be used

Front 16

Variable

Back 16

A name associated with a memory cell whose value can change

Front 17

Variable declarations

Back 17

Statements that communicate to the compiler the names of variables in the program and the kind of information stored in each variable

Front 18

Data type

Back 18

A set of values and operations that can be performed on those values

Front 19

Int

Back 19

Integers.

Faster operations than doubles

Less storage space needed than doubles

Oparations are precise

Having unsigned variables increases their magnitude

Front 20

Double

Back 20

Real numbers (decimal point numbers)

Scientific notation: 1.23 * 10^5 written as 1.23e5 or 1.23E5

Round-off error may occur

Float is a smaller decimal point variable

Front 21

Char

Back 21

Represents an individual character value.

Enclosed in single quotes

Front 22

ASCII Code

Back 22

A particular code that specifies the integer representing each char value

Front 23

Assignment statement

Back 23

An instruction that stores a value or a computational result in a variable

= is the assignment operator

Front 24

Input operation

Back 24

An instruction that copies data from an input device to memory, e.g. scanf

Front 25

Output operation

Back 25

An instruction that displays information stored in memory, e.g. printf

Front 26

Input/Output function

Back 26

A C function that performs an input or output operation

Most common ons supplied through #include

Front 27

the printf function

Back 27

Function arguments include a format string with placeholders and a print list

Front 28

Placeholders for char, int, and double

Back 28

%c char.

%d int.

%f double (printf).

%lf double (scanf)

Front 29

the scanf function

Back 29

Takes function arguments including a format string and a print list including &-operators.

Front 30

7.0/2.0

Back 30

3.5

Front 31

7/2

Back 31

3 (only the integral part)

Front 32

% modulus

Back 32

Returns the remainder of the result of dividing the operands.

Front 33

Mixed-type assignment

Back 33

The expression is evaluated before the assignment is made

Front 34

Type cast

Back 34

Converting an expression to a different type by writing the desired type in parentheses in front of the expression

Front 35

Unary operators

Back 35

Take only one operand

Negation and plus

Front 36

Binary operators

Back 36

Require two operands

E.g. adding, subtracting

Front 37

Rules for evaluating arithmetic expressions

Back 37

1. Parentheses

2. Unary + -

3. *, /, %

4. Binary +, -

Binary operators at the same level are evaluated left to right.

Front 38

Field width

Back 38

The number of columns to use for the display of the value

Front 39

Formatting doubles

Back 39

%n.mf

n = field width

m = decimal places

Front 40

Interactive mode

Back 40

A mode of program execution in which the user responds to prompts by entering data

Front 41

Batch mode

Back 41

A mode of program execution in which the program scans its data from a previously prepared data file

Front 42

Syntax error

Back 42

A violation of the C grammar rules

Detected during compilation

Front 43

Run-time error

Back 43

An attempt to perform an invalid operation

Detected during program execution

Front 44

Logic error

Back 44

An error caused by following an incorrect algorithm

Front 45

Bussar

Back 45

Parallella ledningar i ett datorsystem.

T.ex. bussar för data som transporterar information, bussar för adresser som talar om var i minnet saker ska ta vägen samt kontrollbussar som talar om på vilket sätt något ska ske.