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chapter 3 - Coggle Diagram

- - - - ~allow execution of the same code a number of times
        ~The for loop is most convinient with counting lopps--i.e lopps that based on a counting variable,usually a known number of iteration .
        
        Format:for
        
        Where
        initializeVariable -initializes the loop variable.
        loopCondition - compares the loop variable to some limit value.
        incrementVariable - updates the loop
        
        How it works!!
        ~The initializeVariable runs once, at the start of the loop
        ~The loopCondition is checked. If it's false, quit. If it's true, then:
        ~Run the loop body (statements)
        ~Run the incrementVariable Go back to the loopCondition step and repeat
        
        flowchart
        
        EXEMPLE OF CODING USING FOR STATEMENT
    - - is a statement or block of statements that is repeated as long as some condition is satisfied.
      - While loop has the format: The statements inside the while loop are executed as long as the expression evaluates to true.
      - While
    - - statements inside a do-while loop are executed several times as long as the condition is satisfied
        
        do-while loop has the form:
        ~The main difference between a while and do-while loop - the statements inside a do-while loop are executed at least once.
      - Example of coding using do..while statement
      - Example do..while pseudo code & flowchart
- - - - Read score
        
        Check the grade
        if (score >=80 & & score <= 100)
        grade = 'A'
        else if (score >=66 & & score <79)
        grade = 'B'
        else if (score >=50 & & score <=65)
        grade = 'C'
        else if (score >= 40 & & score <= 49)
        grade = 'D'
        else
        grade = 'F'
        
        Print grade
      - Flowchart
- - - - VARIABLE
        
        -Variables are named memory locations that have types
        -A symbol or name that stands for a value.for example, in the expression
        (x+y)
        -x and y are variables. Variables can represent numeric values, characters, character strings, or memory addresses.
        
        -It is important to understand the different between the name of variable and the value of a variable. The name is the label computer uses to find the correct memory location. The value is the contents of the location.
        There are 2 types of variable
        
        Global
        global variable is a variable declared in the main body of the source code, outside all functions
        
        Local
        local variable is one declared within the body of a function or a block.
      - CONSTANT
        
        Constant refer to fixed values that have a data type
        2 Types of constant :
        a)Defined constants (#define) types of constant
        b)Declared constants(const)
        
        You can define your own names for constants that you use very often without having to resort to memory-consuming variables, simply by using the #define preprocessor directive .
        -Its format is :#define identifier value
        
        EXAMPLE
        Define gravity 9.8
        Define PI 3.14159
        
        With the const prefix you can declare constants with a specific type in the same way as you would do with a variable:
        const int pathwidth =100
        const char grade = 'A'
        Here, path width and grade are two typed constants.
        They are treated just like regular variables except that their values cannot be modified after their definition
      - In a computer language, a reserved word (also known as a reserved identifier) is a word that cannot be used as an identifier, such as the name of a variable, function, or label – it is "reserved from use".
        
        Keywords are also called reserved words because they are words that are reserved by the language for special purposes and cannot be redefined for use as variables or for any other purposes.
      - Rules for naming identifiers.
        
        Must consist of alphabet, digits or unerscore
        
        First character must be an alphabet or an underscore
        
        No space allowed
        
        C++ is a case sensitive language
        
        Cannot duplicate a word
        
        First 31 character of the identifier are significant
      - Declare data types, variable and constants
        We store the variables in our computer's memory, but the computer has to know what kind of data we want to store in them.
        
        In order to use a variable in C++, we must first declare it specifying which data type we want it to be
        
        The syntax to declare a new variable is to write the specifier of the desired data type (like int, bool, float...) followed by a valid variable identifier
        
        example
        int a;
        float mynumber;
        
        These are two valid declarations of variables.
        
        The first one declares a variable of type int with the identifier a.
        
        The second one declares a variable of type float with the identifier mynumber.
        
        Once declared, the variables a and mynumber can be used within the rest of their scope in the program.
        
        If you are going to declare more than one variable of the same type, you can declare all of them in a single statement by separating their identifiers with commas. For example: int a, b, c;
        
        This declares three variables(a,b and c), all of them of type int, and has exactly the same meaning as:
        int a;
        int b;
        int c;
      - Initialization of variables
        
        When declaring a regular local variable, its value is by default undetermined
        
        But you may want a variable to store a concrete value at the same moment that it is declared
        
        in order to do that, you can initialize the variable
        
        Appending an equal sign followed by the value to which the variable will be initialized:
        Type identifier=initial_value;
        float salary=450.50;
        
        For example, if we want to declare an int variable called a initialized with a value of 0 at the moment in which it is declared, we could write: int a = 0