Computer Programming Lab1

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Computer ProgrammingLab1

• Shyh-Kang Jeng
• Department of Electrical Engineering/
• Graduate Institute of Communication Engineering
• National Taiwan University

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Textbook and Course Website

• H. M. Deitel and P. J. Deitel, C How to
  Program, 4th ed., Prentice-Hall, 2003. ??
• http//cc.ee.ntu.edu.tw/skjeng/ComputerProgrammin
  g2004Fall.htm

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Microsoft Visual C
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Projects, Workspaces, and Files
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First Program
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First Program

• // MyFirstProgram\Main.cpp
• // Fig. 1.2 of C How to Program
• // A first program in C
• include ltiostreamgt
• int main()
• stdcout ltlt "Welcome to C!\n"
• return 0

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Preparing and Running a Program

• New Projects Console Application
• Location, Project name
• New Files C Source File, File
• Editing the source program .h or .cpp
• Build Compile .cpp
• Build Build .exe
• Execute .exe

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Good Programming Practices

• Keep it simple
• Read the manuals/on line help (MSDN)
• Write small programs to learn how a C feature
  works

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Escape Sequences

• \n newline
• \t horizontal tab
• \r carriage return
• \a alert
• \\ backslash
• \ double quote

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Adding Two Integers
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Adding Two Integers

• // AddingTwoIntegers\Main.cpp
• // Fig. 1.6 of C How to Program
• // Addition program.
• include ltiostreamgt
• int main()
• int integer1// first number to be input by user
• int integer2// second number to be input by
  user
• int sum // variable in which sum will be stored
• stdcout ltlt "Enter first integer\n" // prompt
• stdcin gtgt integer1
• stdcout ltlt "Enter second integer\n"
• stdcin gtgt integer2
• sum integer1 integer2
• stdcout ltlt "Sum is " ltlt sum ltlt stdendl
• return 0

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Good Programming Practices

• Choose meaningful variable name
• Avoid identifiers begin with underscores and
  double underscores
• Place a blank line between declaration and
  adjacent executable statements

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Memory Concepts

• stdcin gtgt integer1
• Assume user entered 45
• stdcin gtgt integer2
• Assume user entered 72
• sum integer1 integer2

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Using the Debugger
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Arithmetic Operators

• Multiplication
• /
• Division
• Integer division truncates remainder
• 7 / 5 evaluates to 1
• Modulus operator returns remainder
• 7 5 evaluates to 2

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Precedence of Arithmetic Operators
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Equality and Relational Operators
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Relational Operators Test
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Relational Operators Test (1)

• // RelationalOperatorsTest\Main.cpp
• // Fig. 1.14 of C How to Program
• // Using if statements, relational
• // operators, and equality operators
• include ltiostreamgt
• using stdcout
• using stdcin
• using stdendl
• int main()
• int num1 // first number to be read from user
• int num2 // second number to be read from user

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Relational Operators Test (2)

• cout ltlt
• "Enter two integers, and I will tell you\n"
• ltlt "the relationships they satisfy "
• cin gtgt num1 gtgt num2
• if( num1 num2 )
• cout ltlt num1 ltlt " is equal to " ltlt num2 ltlt
  endl
• if( num1 ! num2 )
• cout ltlt num1 ltlt " is not equal to " ltlt num2 ltlt
  endl
• if( num1 lt num2 )
• cout ltlt num1 ltlt " is less than " ltlt num2 ltlt
  endl

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Relational Operators Test (3)

• if( num1 gt num2 )
• cout ltlt num1 ltlt " is greater than " ltlt num2 ltlt
  endl
• if( num1 lt num2 )
• cout ltlt num1 ltlt " is less than or equal to "
• ltlt num2 ltlt endl
• if( num1 gt num2 )
• cout ltlt num1 ltlt " is greater than or equal to "
• ltlt num2 ltlt endl
• return 0

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Good Programming Practices

• There should be no more than one statement per
  line in a program
• Split a lengthy statement across lines
  consistently and carefully to make it easy to read