lecture 5: computer languages. programming environments (ide) cos120 software development using c++...
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Lecture 5: Computer Languages.Programming Environments
(IDE)
COS120 Software Development Using C++ AUBG, COS dept
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Lecture Contents:
Programming Environments. Integrated Development Environments (IDE)
Microsoft Visual Studio: C++ IDE Introduction to project concept
– Solution and project(s) Sample programs in C++
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Previous lecture reminder
Title:
A Tutorial Introduction to C++
Source: Friedman/Koffman, Chapter 02
Have a quick look at next approx 40 slides to refresh your knowledge on previous lecture
Overview of C++
Chapter 2
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2.1 C++ Language Elements
Comments make a program easier to understand
// Used to signify a comment on a single line
/* Text text */ use if comments on multi lines
Don’t embed comments within /* */ comments
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Compiler Directives
#include– Compiler directive– Processed at compilation time– Instructs compiler on what you want in the program
#include <iostream>– Adds library files to program– Used with < >– Also “ “ user defined
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Compiler Directives
Stream data type– Object that is a stream of characters– Defined in iostream– Entered on the keyboard (cin)– Displayed on monitor (cout)
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Declarations
Based on data needs (data identifiers) Each identifier needed must be declared Comma used to separate identifiers cin and cout are standard, undeclared identifiers
– Special elements called streams– cin - input stream– cout - output stream– Included with the iostream, not declared
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Executable Statements
cout get outputcout << "\nEnter the fabric size in square meters:";
cin get inputcin >> sizeInSqmeters;
AssignmentsizeInSqyards = metersToYards * sizeInSqmeters;
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2.2 Reserved Words and Identifiers
Reserved words have special meanings– Can NOT be used for other purposes (const, float and void are some examples)
Identifiers (variables)– Used to store data by the program (user
defined)– Valid identifiers - letter, letter1, _letter– Invalid identifiers - 1letter, const, hell o
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Reserved Words and Identifiers
Special symbols– C++ has rules for special symbols – = * ; { } ( ) // << >>
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Upper and Lower Case
C++ - case sensitive language– Compiler differentiates upper & lower case– Identifiers can be either – Be careful though (cost != Cost)
Blank spaces– Use space to make program readable– Use care in placing spaces
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2.3 Data Types and Declarations
Predefined data types– int (integer numbers)
• Positive or negative whole numbers• 1000 12 199 100000• INT_MAX - largest int allowed by compiler
– float or double (real numbers)• Positive or negative decimal numbers• 10.5 1.2 100.02 99.88
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Data Types and Declarations
Predefined data types– bool (Boolean)
• true• false
– char (Characters)• Represent single characters
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Data Types and Declarations
The basic integer type is int– The size of an int depends on the machine
and the compiler• On PC’s it is normally 16 or 32 bits
Other integers types– short: typically uses less bits– long: typically uses more bits
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Data Types and Declarations
Floating-point types represent real numbers– Integer part– Fractional part
The number 108.1517 breaks down into the following parts– 108 - integer part– 1517 - fractional part
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Data Types and Declarations
C++ provides three floating-point types:
– float– double– long double
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Data Types and Declarations
Predefined data types– char (characters)
• Individual character value (letter or number)• Character literal enclosed in single quotes ‘A’
– bool (true / false) Ordinal types
– int bool char– Values can be listed
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Data Types and Declarations
Character type char is related to the integer types
Characters are encoded using a scheme where an integer represents a particular character
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Data Types and Declarations
ASCII is the dominant encoding scheme– Examples
• ' ' encoded as 32• '+' encoded as 43• 'A' encoded as 65• 'Z' encoded as 90• 'a' encoded as 97 • 'z' encoded as 122
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string Class
String object data type– A literal string constant is a sequence of zero or
more characters enclosed in double quotes– "Are you aware?\n"– Individual characters of string are stored in
consecutive memory locations– The null character ('\0') is appended to
strings so that the compiler knows where in memory string ends
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string Class
String literal– "A"– "1234"– "Enter the distance:"
Additional data types included in library#include <string>– Various operations on strings
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Declarations
Identifiers should be – Short enough to be reasonable to type (single word is
norm)• Standard abbreviations are fine (but only standard
abbreviations)
– Long enough to be understandable• When using multiple word identifiers capitalize the first
letter of each word
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Declarations
Examples– char response;– int minelement;– float score;– float temperature;– int i;– int n;– char c;– float x;
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Constant Declarations
Types of named constants:– integer – float– char– bool– string objects
Associate meaningful terms– const float PAYRATE = 10.25;
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Hello.cpp –full text of program
// FILE: Hello.cpp// DISPLAYS A USER'S NAME#include <iostream>#include <string>using namespace std;int main(){
char letter1, letter2;string lastName;
// Enter letters and print message. cout << "Enter 2 initials and last name: "; cin >> letter1 >> letter2 >> lastName; cout << "Hello " << letter1 << ". " << letter2 << ". " << lastName << "! ";
cout << "We hope you enjoy studying C++." << endl; return 0;}
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Hello.cpp
Program output
Enter first 2 initials and last name and press return: EBKoffman
Hello E. B. Koffman! We hope you enjoy studying C++.
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2.4 Executable Statements
Memory status– Before and after
Assignments– Form: result = expression;– sizeInSqyards = metersToYards * sizeInSqMeters;– sum = sum + item;
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Arithmetic Operators
+ Addition - Subtraction * Multiplication / Division % Modulus
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Input / Output Operations
Input– #include <iostream> library– cin >> sizeInSqmeters;
Extracted from cin (input stream) >> Directs input to variable cin associated with keyboard input (stdin) Used with int, float, char, bool and strings
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Data Types and cin
Don’t mix types with cinint x;cin >> x;
Keyboard input
16.6
Value placed in x would be 16
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Other Characteristics of cin
Leading blanks ignored (floats, int, char, bool and
strings) Char read 1 at a time (1 non blank) Case issues int or float will read until space Strings same as int and float
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General Form for cin
Form: cin >> dataVariable;
cin >> age >> firstInitial;
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Program Output
Output stream cout << Output operator (insertion operator)
– cout << “my height in inches is: “ << height; Blank lines
– endl or “\n” or ‘\n’
Form: cout << dataVariable;
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2.5 General Form of a C++ Program
General program form– Function basic unit (collection of related statements)– A C++ program must contain a main function
void main() { . . . }
– int - function returns integer value– void - function does not return value– main - lower case with ()– { } - Braces define the function body
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General Form of a C++ Program
General form of function body parts
–Declaration statements• Variables and constants
–Executable statements• C++ statements
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General Form of a C++ Program
General form// File: filename// Program description:#include directivesint main(){
Declarations section
Executable statements section
}
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General Form
// Name: Mike Hudock
// Date: March 10, 2012
// Files: file1.cpp
// Changes :
// Program description:
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General Form
Use comments throughout code to highlight points of interest
Strange identifiers Function explanations Algorithm definitions
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2.6 Arithmetic Expressions
int data type– + - * /, Assignment, input and output on int– % Only used with int
Examples of integer division15 / 3 = 515 / 2 = 70 / 15 = 0
15 / 0 undefined
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Modulus and Integer
Used only with integer and yields remainder
Examples of integer modulus7 % 2 = 1
299 % 100 = 99
49 % 5 = 4
15 % 0 undefined
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Mixed-type Assignments
Expression evaluated Result stored in the variable on the left side C++ can mix types
float a, b, x;int m, n;a = 10;b = 5;x = m / n;
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Expressions With Multiple Operators
Operator precedence tells how to evaluate expressions
Standard precedence order– () Evaluated first, if nested innermost
done first– * / % Evaluated second. If there are several,
then evaluate from left-to-right– + - Evaluate third. If there are several,
then evaluate from left-to-right
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Mathematical Formulas in C++
a = bc not valid C++ syntax* Operator a = b * c;
m =
( ) And / m = (y - a) / (x + b);
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2.8 Common Programming Errors
Syntax– Programs rarely compile– Something always goes wrong– Systematic solutions
Compiler not descriptive– Look at line number before and after error– Watch missing ; and }
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Common Programming Errors
Run-time errors– Illegal operation (divide by 0)
Logic errors– Program functions differently than you expect
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IDE
MS Visual Studio
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Introduction toMS Visual C++ 2010
When you activate IDE for the first time, it’s time for you to make your choice:
General development settings Or C++ development settings Or …
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Intro to MS Visual C++Creating Unmanaged Application
To build a console application that will run without .NET framework, follow these steps:1. Open Visual Studio.2. On the Start Page, click New Project… . If the Start Page isn’t visible, Choose File,
New, Project.3. Select the Visual C++\Win32 from Installed Project Templates on the left and select
Win32 Console Application Project type on the right.4. Enter project name, for example ConsoleApplication1, project location, for
example Q: drive and click OK.5. Click Finish from the wizard that appears.The wizard generates the skeleton of an unmanaged C++ application.
To build the project, follow these steps:6. Choose Build, Build Solution or press F7
To run the project, follow these steps:7. Choose Debug, Start Without Debugging or press Ctrl+F5
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Exercise 5.1
Build and run a program: To compute and display the volume of a pool.
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Exercise 5.4
Build and run a program: To convert Celsius degrees to Fahrenheit degrees
Fahr = 9./5.*Cel+32
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Exercise 5.5
Build and run a program: To convert Fahrenheit degrees to Celsius degrees
Cel = 5./9.*(Fahr-32)
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Exercise 5.3
Build and run a program: To add, subtract, multiply and divide two numeric values.
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Exercise 5.2
Build and run a program: To convert feet and inches to meters.
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Before lecture end
Lecture:Computer Languages.
Programming environments (IDE)
More to read:Friedman/Koffman, Chapter 02
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Thank You
For
Your Attention!