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Programming in C.pptx
- 1.
- 2. What is C? Cis a high level and general purpose programming language that is ideal for developing firmware or portable applications.
- 3. C was developedat Bell Labs by Dennis Ritchie for the Unix Operating system in the early 1970s C is strongly associated with UNIX, as it was developed to write the UNIX operating system.
- 4. Why Learn C? Itis one of the most popular programming language in the world If you know C, you will have no problem learning other popular programming languages such as Java, Python, C++, C#, etc, as the syntax is similar C is very fast, compared to other programming languages, like Java and Python
- 5. C is veryversatile; it can be used in both applications and technologies Get Started With C To start using C, you need two things: A text editor, like Notepad, to write C code A compiler, like GCC, to translate the C code into a language that the computer will understand
- 6. An IDE (IntegratedDevelopment Environment) is used to edit AND compile the code. Popular IDE's include Code::Blocks, Eclipse, and Visual Studio. These are all free, and they can be used to both edit and debug C code.
- 7. C Syntax #include <stdio.h> intmain() { printf("Hello World!"); return 0; } Line 1: #include <stdio.h> is a header file library that lets us work with input and output functions, such as printf() (used in line 4). Header files add functionality to C programs.
- 8. Line 2: Ablank line. C ignores white space. But we use it to make the code more readable. Line 3: Another thing that always appear in a C program, is main(). This is called a function. Any code inside its curly brackets {} will be executed. Line 4: printf() is a function used to output/print text to the screen. In our example it will output "Hello World".
- 9. Note that: EveryC statement ends with a semicolon ; Note: The body of int main() could also been written as: int main(){printf("Hello World!");return 0;}
- 10. Line 5: return0 ends the main() function. Line 6: Do not forget to add the closing curly bracket } to actually end the main function.
- 11. C Output (PrintText) The printf() function is used to output values/print text: You can add as many printf() functions as you want. However, note that it does not insert a new line at the end of the output: #include <stdio.h> int main() { printf("Hello World!"); printf("I am learning C."); return 0; }
- 12. New Lines To inserta new line, you can use the n character: Example #include <stdio.h> int main() { printf("Hello World!n"); printf("I am learning C."); return 0; }
- 13. You can alsooutput multiple lines with a single printf() function. However, be aware that this will make the code harder to read: #include <stdio.h> int main() { printf("Hello World!nI am learning C.nAnd it is awesome!"); return 0; } Two n characters after each other will create a blank line:
- 14. What is nexactly? The newline character (n) is called an escape sequence, and it forces the cursor to change its position to the beginning of the next line on the screen. This results in a new line.
- 15. Examples of othervalid escape sequences are: Escape Sequence Description t Creates a horizontal tab Inserts a backslash character () " Inserts a double quote character
- 16. C Variables Variables arecontainers for storing data values. In C, there are different types of variables (defined with different keywords), for example: int - stores integers (whole numbers), without decimals, such as 123 or -123 float - stores floating point numbers, with decimals, such as 19.99 or -19.99 char - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes
- 17. To create avariable, specify the type and assign it a value: Declaring (Creating) Variables Syntax type variableName = value; C Variable Names All C variables must be identified with unique names.
- 18. These unique namesare called identifiers. Identifiers can be short names (like x and y) or more descriptive names (age, sum, totalVolume). Note: It is recommended to use descriptive names in order to create understandable and maintainable code: To output variables in C, you must get familiar with something called "format specifiers".
- 19. Format Specifiers Format specifiersare used together with the printf() function to tell the compiler what type of data the variable is storing. It is basically a placeholder for the variable value. A format specifier starts with a percentage sign %, followed by a character. For example, to output the value of an int variable, you must use the format specifier %d or %i surrounded by double quotes, inside the printf() function:
- 20. Example // Create variables intmyNum = 5; // Integer (whole number) float myFloatNum = 5.99; // Floating point number char myLetter = 'D'; // Character // Print variables printf("%dn", myNum); printf("%fn", myFloatNum); printf("%cn", myLetter);
- 21. To print othertypes, use %c for char and %f for float: To combine both text and a variable, separate them with a comma inside the printf() function: Example int myNum = 5; printf("My favorite number is: %d", myNum);
- 22. To print differenttypes in a single printf() function, you can use the following: #include <stdio.h> int main() { int myNum = 5; char myLetter = 'D'; printf("My number is %d and my letter is %c", myNum, myLetter); return 0; }
- 23. C Variable Names AllC variables must be identified with unique names. These unique names are called identifiers. Identifiers can be short names (like x and y) or more descriptive names (age, sum, totalVolume). Note: It is recommended to use descriptive names in order to create understandable and maintainable code:
- 24. C Data Types Asexplained in the Variables chapter, a variable in C must be a specified data type, and you must use a format specifier inside the printf() function to display it:
- 25. #include <stdio.h> int main(){ // Create variables int myNum = 5; // Integer (whole number) float myFloatNum = 5.99; // Floating point number char myLetter = 'D'; // Character // Print variables printf("%dn", myNum); printf("%fn", myFloatNum); printf("%cn", myLetter); return 0; }
- 26. Basic Data Types Thedata type specifies the size and type of information the variable will store.
- 27. Data Type SizeDescription int 2 or 4 bytes Stores whole numbers, without decimals. float 4 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 7 decimal digits. Double 8 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 15 decimal digits. char 1 byte Stores a single character/letter/number, or ASCII values.
- 28. Basic Format Specifiers FormatSpecifier Data Type %d or %i int %f float %lf double %c char %s Used for strings
- 29. Constants When you don'twant others (or yourself) to override existing variable values, use the const keyword (this will declare the variable as "constant", which means unchangeable and read-only): Notes On Constants When you declare a constant variable, it must be assigned with a value:
- 30. Example Like this: const intminutesPerHour = 60;
- 31. Prepared by: Teresita C.Dapulase Reference: https://www.w3schools.com/c/index.php