IDE – Integrated Development Environment
Algorithm – approach or method used to solve a problem
- If we are to create a program that tests if a number is odd or even:
- The statements that solve the problem become the program
- The method that is used to test if the number is odd or even is the algorithm
- To write a program, you need to write the instructions necessary to implement the algorithm. These instructions would be express in the statements of a particular computer language, such as Java, C++, Objective-C or C
Program – the statements that solve a problem
- A computer is a machine that does what was told. A program tells the computer what to do. The algorithm is the process behind a program that tells the computer what to do. A programmer maps, designs, and creates the program.
Computer’s Instruction Set – formed by basic operations
- To solve a problem using a computer, you must provide a solution to the problem by sending instructions to the instruction set.
- A computer program sends the instructions necessary to solve a specific problem.
Higher Level Programming Languages – make it easier to write programs
Compilers
- a program that translates the high-level language source code into the detailed set of machine language instructions the computer requires
- does the high-level thinking and the compiler generates the tedious instructions to the cpu
- will check that your program has valid syntax for the programming language that you are compiling
- finds errors and reports them to you and doesn’t produce an executable until you fix them
Writing C Program
- Define the program objectives
- Understand the requirements, you have to get a clear idea of what you want the program to accomplish
- Design the program
- Decide how the program will meet the above requirements
- What should the user interface be like
- How should the program be organized
- Write the code
- Start implementation, translate the design in the syntax of C
- Use a text editor to create what is called a source code file
- Compile
- translate the source into machine code (executable code)
- consists of detailed instructions to the CPU expressed in a numeric code
- Run the program
- the executable file is a program you can run
- Test and Debug
- debugging – finding and fixing program errors
- Maintain and modify the program
- after the release, have to continue to fix new bugs or add new features
Develop the habit of planning before coding.
Work in small steps and constantly test.
C
- a general-purpose, imperative computer programming language that supports structured programming
- uses statements that change a program’s state, focuses on how
- one of the most widely used programming languages of all time
- reliable and readable program
- used on everything
- preferred language for producing word processing programs, spreadsheets, and compilers
- popular for programming embedded systems
- continues to play a strong role in the development of Linux
- easy to modify and adapt to new models or languages
- C is a subset of C++ with object-oriented programming tools added
Features
- produces compact and efficient programs
- one of the most important programming languages and will continue to be so
- portable
- programmer-oriented
- pointers play a big role in C
- direct access to memory
- supports efficient use of pointers
Disadvantages
- use of pointers is problematic and abused
- you can make programming errors that are difficult to trace
- there is opportunity to write obscure code
kernel – the brain of operating system
Four Fundamentals Tasks in the Creation of any C Program
- Editing – the process of creating and modifying your C source code
- source code is inside a file and contains the program instructions you write
- choose a wise name for your base file name (all source files end in the .c extension)
- we will use an IDE (code blocks) for this class, but you can use any editor to create your source code
- Compiling
- a compiler converts your source code into machine language and detects and reports errors in your code
- the input to the compiler is the file you produce during your editing (source file)
- Two-Stage Process
- Preprocessing phase – code may be modified or added to
- Actual compilation that generates the object code
- the standard command to copile your C programs will be cc (or the GNU compiler, which is .gcc)
- cc -c myprog.c or gcc -c myprog.c
- if you omit the -c flag, your program will automatically be linked as well
- Linking
- the purpose of the linking phase is to get the program into a final form for execution on the computer
- linking usually occurs automatically when compiling depending on what system you are on, but, can sometimes be a separate command
- success fill produce and executable file
- Windows
.exe
- UNIX/Linux
a.out
- Windows
- Executing
syntactic error - expression that has unbalanced parentheses
semantic error - use of a variable that is not defined
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