CCS2 - Final

C programming language

#include - preprocessing directive: instructions to the compiler that our program will need to include

main () - main entry point of the program, must have only one.

{ - open curly brace to begin statements inside the main.

} - ends statements

printf(“hello world.”);

• example of program statement

• allows us to display strings to the screen

Note:

• C programming is case-sensitive

• spacing and indention do not affect execution. only makes it more readable

The main ()

C defaults to int. C is not strict on return statement.

void main () - no need for return statement

Comments

// - single line

/* */ - multi-line

• inserting explanations

• hide code

Special character: \n, \t

\n - adds new lines to the display

\t - adds 5 empty spaces instead of new line

Displaying variables - DATA TYPES

• Integer - whole number positive or negative and 0

• Float - rational numbers (decimal) except 0 but 0.0 included

• Character - single symbol ‘ ‘

• String - set of characters “ “

Variables

placeholders for values.

• must not have the same name as predefined words in the language

• cannot have numbers as first character

• no spaces or special characters

• unique within the same program

assigning variables - left gets right

Arithmetic operators

addition, subtraction, multiplication, division, modulo

precedence - parentheses, multi and divi, add and subtract

assignment ops

+=, -=, *=, /=, %=

constant declaration #define <variable> <value>

increment decrement: ++ --

a++ postfix compiler sees ‘a’ first

++a prefix compiler sees ++ first

scanf

string: contains data format “%d” and argument: corresponds data type of variable &num

Making programs that solve problems

G – Given

R – Required

E – Equation

S – Solution

A – Answer

oval - terminal, start or end

rectangle - process symbol

diamond - decision symbol

parallelogram - input/output symbol

arrows - connect the symbols, show relationship

connectors

• On-page connector - replace long lines on flowchart page, circle

• Off-page connector - target is on other page, five-pointed polygon

• used in pairs

• first connectors is the end, second is the continuation

If

• specifies condition and executes statements only if condition is true

If-else

• condition is true, first part executes, otherwise second part executes\

Else if

• specify new conditions if first condition is false

nested if

• multple conditions apply

• condition depends on another condition

shorthand ternary

• takes less space writes in shortest way possible

first is comparison, second is result if true, third is result if false

Switch

• usefule if we have to choose between n numbers of alternatives

• execute one code block among many alternatives, if-else-if ladder statement

Loops

• used to repeat block of code until condition is met

• entry controlled

  • for and while

• exit controlled

  • evaluated at the end of loop

  • do-while

•Start

•Stop

•Repeating Action(s)

•condition to continue

•Process for the loop to continue and eventually reach the “stop”

Do-While

• the body of do is executed once before testing expression

For

• for (initializationStatement; testExpression; updateStatement){
  // statements inside the body of loop
  }
  

Jumping Statements

Jumping statements are generally used within a branching statement. used to jump out of loops

• break

  • ends the loop immediately when it is encountered.

  • terminates only the nested loop if used in nested loops

• Continue

  • used to skip the statements if we dont want to write any statement inside a condition.

• Goto

  • can be used anywhere unconditionally in between the program. Jump the control anywhere in between the program

• Exit

  • use to terminate a program

• gotoxy sets curosr to a pos

Functions

• block of statements to perform tasks

• instead of writing a block of code again and again, we can create a function and call it as many times as required.

• when the function is called the controller is passed to the function then return back from where it was called

• reduces the size of a program