C programming Tutorial Session 1

OBJECTIVES
• Differentiate between command, Program, and Software
• Explain the beginning of C
• Explain when and why C is used
• Discuss the c program structure
• Discuss Algorithm
• Draw Flowcharts
• List the symbol used in flowcharts
Presented by: Muhammad Ehtisham Siddiqui (BSCS)
2

COMMAND, PROGRAM AND SOFTWARE
• In computing, a command is a directive to a computer program acting as an
interpreter of some kind, in order to perform a specific task.
• A program is a set of instructions(commands) written in computer language to
provide solution for a particular problem using computing devices is commonly
referred as Program.
• software is a collection of individual programs well packaged to run on a computer.
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COMMAND, PROGRAM AND SOFTWARE
4
Software
Program Program
Command Command Command Command

BEGINNING OF C
• C programming language was invented by
Dennis Ritchie at the Bell Laboratories in 1972.
5

APPLICATION AREAS OF C PROGRAMMING
• C was initially used for Systems programming
• A System programs forms a portion of the operating system of the computer or it
support utilities
• Operating systems, Interpreters, Editors, Assembly programs are usually called
system programs
• The UNIX operating system was developed using C
• There are C compilers are available for almost all types of PC’s
6

MIDDLE LEVEL LANGUAGE
C is called middle-level language because it is actually bind the gap between a
machine level language and high-level languages. User can use c language to do
System Programming (for writing operating system) as well as Application
Programming (for generate menu driven customer billing system ).
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STRUCTURED LANGUAGE
• C is called a structured programming language because to solve a large problem
• C allows compartmentalization of code and data
• C programming language divides the problem into smaller modules called
functions or procedures each of which handles a particular responsibility
• The program which solves the entire problem is a collection of such functions
For Ex: We have to develop a calculator . So we must have to divide programs into
functions of Addition, Subtraction, Multiplication, Division etc.
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ABOUT C PROGRAMMING (keywords)
• There are 32 Keywords in C
• Keywords are those words whose meaning is already defined by Compiler
• Keywords cannot be used as a variable or function name
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C PROGRAMMING STRUCTURE [ main() ]
 C programs are divided into units called functions
 Identify the start of program
 Every C program has a main ()
 Main() is a keyword , we must not used it for any other variable
 4 common ways of main declaration
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C PROGRAMMING STRUCTURE[Delimiters]
• A delimiter is one or more characters that separates text strings
• Common delimiters are commas (,), semicolon (;), quotes ( ", ' ), braces ({}), pipes (|),
or slashes ( / )
• C programming Delimiters are as follows
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Delimiter Symbol Use
Colon : Useful for label
Semicolon ; Terminates statements
Parenthesis () Used in expression and function
Square brackets [] Used for array declaration
Curly braces {} Scope of statement
Hash # Preprocessor directive
Comma , variable separator
#include<stdio.h>
void main()
{
int a,b,c[10];
printf("hi");
}

C PROGRAMMING STRUCTURE[Comment]
• In computer programming, a comment is a programmer-readable explanation or
annotation in the source code of a computer program.
• They are added with the purpose of making the source code easier for humans to
understand, and are generally ignored by compilers and interpreters.
• In C Comment begin with /* and are terminated with */
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THE C LIBRARY
• All C compilers come with a standard library of functions
• A function written by a programmer can be placed in the library and used
when required
• Some compilers allow functions to be added in the standard library
• Some compilers require a separate library to be created
• C Standard library functions or simply C Library functions are
inbuilt functions in C programming.
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COMPILING AND RUNNING A PROGRAM
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PROGRAMMING APPROACH FOR SOLVING A PROBLEM
What is algorithm ?
Algorithm is a set of instruction performed by programmer to solve a problems
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3. Process the information
1. Understand the problem
clearly
4. Arrive the solution
2. Understand the problem
clearly
To solve problems

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• Pseudocode is a simple way of writing programming code in English.
• Pseudocode is not actual programming language.
• For Example:
1. Start Program
2. Enter two numbers, A, B
3. Add the numbers together
4. Print Sum
5. End Program
Each pseudocode starts with a BEGIN/START To show some value ,
the word DISPLAY/PRINT is used The pseudocode finishes with an END

18
• What is Flowchart ?
Flowchart is a diagrammatic representation of an algorithm. Flowchart are very helpful
in writing program and explaining program to others.

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• Flowchart Symbol
Different symbols are used for different states in flowchart, For example: Input /
Output and decision making has different symbols. The table below describes all the
symbols that are used in making flowchart

20
• Flowchart to add two numbers?

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• Flowchart with If Construct

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• Flowchart with If Else

23
• Flowchart with For Loop

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C programming Tutorial Session 1

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