24-311: Numerical Method

C++ Programming Tutorial

======================================================================
How to compile and run a simple C++ code.

    1. write/edit source code (*.cpp, *.C, *.c++, *.cxx, *.h, etc.)
    2. Compile source code => object code (*.obj, *.o, etc.)     => fix bugs
    3. Link/build object code => executable code (*.exe, *, etc) => fix bugs
    4. Run excecutable code                                      => fix bugs

    Typical C++ source codes consist of:
        function definitions
        variable declarations
        statements

    --------------------------------------------------
    // test01  <= this is a comment
    /* another form of comment */

    #include <iostream.h>
    #include <stdio.h>

    void main(){
        cout << "The volume of the box is ";
        cout << 11 * 9 * 40;
        cout << endl;

        cout << "The volume of the box is "
             << 11 * 9 * 40
             << endl;

        cout << "The volume of the box is " << 11 * 9 * 40 << endl;

        printf("The volume of the box is %d \n", 11 * 9 * 40);
    }
    --------------------------------------------------

======================================================================
How to declare variables.

    identifier: a name consisting of letter and digits, the first of
        which must be a letter, with underscore counting as a letter

    variable: 
        - the name of a chunk of computer memory
        - each variable refers to a chunk of memory
        - data type: the size of the chunk and the way the bits 
          in the chunk are interpreted
            character:      char
            integer:        short, int, long
            floating point: float, double, long double

    variable declaration
    
    --------------------------------------------------
    void main(){
        int height;
        int width;
        int length;
        ...
    }
    --------------------------------------------------
    void main(){
        int height, width, length;
        ...
    --------------------------------------------------
    void main(){
        int height = 5, width = 6, length = 7;
        ...
    --------------------------------------------------


======================================================================
How to write statements that read input from your keyboard.     
    
    --------------------------------------------------
    #include <iostream.h>
    void main(){
        int height, width, length;
        
        cout << "Please type height, width, and length." << endl;
        cin >> height >> width >> length;
        cout << "The volume is " << height*width*length <<endl;
    }
    --------------------------------------------------

    If you with to redirect input from your keyboard to a file, then
    instantiate the following pattern:

        PROGRAM_NAME < FILE_NAME


======================================================================
How to write output to and read input from a file.

    --------------------------------------------------
    #include <iostream.h>
    #include <fstream.h>
    void main(){
        int h, w, l;
        
        ofstream write_file("output.txt");
        write_file << "I hate Micro$oft." << endl;
        
        ifstream read_file("input.txt");
        read_file >> h >> w >> l;
        cout << "Volume = " << h*w*l;
    }
    --------------------------------------------------

======================================================================
How to define simple functions.

    DATA_TYPE FUNCTION_NAME (DATA_TYPE PARAMETER,
                             ...,
                             DATA_TYPE PARAMETER) {

        VARIABLE_DECLARATION
        ...
        VARIABLE_DECLARATION

        STATEMENT
        ...
        STATEMENT
    }

    --------------------------------------------------
    #include <iostream.h>

    void display_volume(int h, int w, int l);
    
    main(){
        int height, width, length;
        
        cout << "Please type height, width, and length." << endl;
        cin >> height >> width >> length;
        display_volume(height, width, length);
    }

    void display_volume(int h, int w, int l){
        int volume;

        volume = h*w*l;
        cout << "The volume is " << volume <<endl;
    }
    --------------------------------------------------

    Local and global variables
        extent: the time during which a chunk of memory is allocated
                for the variable
        scope:  the portion of a program where that variable can be
                evaluated or assigned

    Unlike most languages, C++ allows you to define multiple functions
    with the same name, as long as each version has a different
    arrangement of parameter data types. ("overloaded")
    
    You cannot propagate the type of parameters, e.g., the following
    does not work:
        void display_volume(int h, w, l){
            ...
        }

    You can also define a function to return volume as an integer number:
    --------------------------------------------------
    int volume(int h, int w, int l){
        return h*w*l;
    }
    --------------------------------------------------

======================================================================
Skipping...
How to create classes and objects.
How to define constructor member functions.
How to define reader and write member functins.
How to benefit from data abstraction.
How to protect member variables from harmful reference.
How to define classes that inherit variables and functins.


======================================================================
How to perform tests using numerical predicates.

    ==, !=, >, <, >=, <=

    The value of the expression using a numerical predicate can be:
        0   False
        1   True

    Use the and operator, &&, and the or operator, ||, to combine
    boolean expressions.
        the value of (2 < 3 && 3 > 4) is 0
        the value of (2 < 3 || 3 > 4) is 1

    A common error is to write = when you intend to check for equality.

    != means "Are two numbers not equal?"  ! can appear alone, in which
    case the ! character denotes the "not" operator, e.g.,
        the value of !0 is 1 and !1 is 0
        the value of !(6 < 3) is 1
        the value of !(6!=3) is 0

    If you want to force the conversion of a value of one type into
    the corresponding value of another type, then you must "cast" the
    value by the following pattern:
        (DATA_TYPE) EXPRESSION
    You must cast one to machtch the type of the other if you want
    to compare two numbers of different types.


======================================================================
How to write conditional statements.

    When boolean expression of an if statement evaluates to any
    integer other than 0, C++ considers the expression to be true
    and excecute the embedded statement.
        if (BOOLEAN_EXPRESSION)
            IF_TRUE_STATEMENT
        else
            IF_FALSE_STATEMENT

    Compound statement
        {
            statement_1
            ...
            statement_n
        }

    The value-producing conditional-operator expression:

        BOOLEAN_EXPRESSION ? IF_TRUE_EXPRESSION : IF_FALSE_EXPRESSION

    --------------------------------------------------
    #include <iostream.h>
    main(){
        int change;
        
        cout << "Temparature change = ";
        cin >> change;
        cout << "The temperature has changed by "
             << change
             << (change == 1 ? "degree" : "degrees")
             << endl;
    }
    --------------------------------------------------


======================================================================
How to write iterative statements.
    
    while (BOOLEAN_EXPRESSION)
        EMBEDDED_STATEMENT

    for (ENTRY_EXPRESSION;
         BOOLEAN_EXPRESSION;
         CONTINUATION EXPRESSION)
        EMBEDDED_STATEMENT

    If you want to increment or decrement the value of a variable by 1:
        ++VARIABLE_NAME
        --VARIABLE_NAME

    --------------------------------------------------
    #include <iostream.h>
    main(){
        int i;
        for (i=0; i<5; i++)
        cout << i << endl;
    }
    --------------------------------------------------


======================================================================
How to work with arrays of numbers.

    --------------------------------------------------
    #include <iostream.h>
    void main(){
        const int n = 5;
        float v[n] = {3.0, 4.0, 5.0, 6.0, 7.0};
    
        for(int i = 0; i < n; i++) 
            cout << "v[" << i << "] = " << v[i] << endl;
    }
    --------------------------------------------------
    #include <iostream.h>
    void main(){
        const int n = 3, m = 4;
        float v[n][m] = {{1.0, 2.0, 3.0, 4.0},
                         {5.0, 6.0, 7.0, 8.0},
                         {9.0, 10.0, 11.0, 12.0}};
    
        for(int i = 0; i < n; i++)
            for(int j = 0; j < m; j++)
                cout << "v[" << i << "][" << j << "] = " << v[i][j] << endl;
    }
    --------------------------------------------------
    #include <iostream.h>
    void display_matrix(float v[3][4]);
    void main(){
        float v[3][4] = {{1.0, 2.0, 3.0, 4.0},
                         {5.0, 6.0, 7.0, 8.0},
                         {9.0, 10.0, 11.0, 12.0}};

        display_matrix(v);
    }
    
    void display_matrix(float v[3][4]){
        for(int i = 0; i < 3; i++)
            for(int j = 0; j < 4; j++)
                cout << "v[" << i << "][" << j << "] = " << v[i][j] << endl;
    }
    --------------------------------------------------