1. I NTRODUCTION TO P ROGRAMMING Lecture No. 1 and 2 Combined Lahore Leads University 21 st October 2013

2. D EFINITION OF A C OMPUTER Computer is an advanced Electronic Device that takes raw data as input from the user and processes these data under the control of set of instructions (Called Programs) and gives the result (output) and saves the output for the future use.

3. T YPES OF P ERSONAL C OMPUTERS Six Primary Types of Computers are; 1. Desktop Computers 2. Workstations 3. Notebook Computers 4. Tablet Computers 5. Handheld Computers 6. Smart Phones

4. O VERVIEW What is Programming? Why Programming is Important? What Skills are Needed? Develop a Basic Recipe for writing programs Points to Remember

5. W HAT IS P ROGRAMMING ? As this course is titled as “Introduction to Programming” therefore it is most essential and appropriate to understand what programming really means. The Definition of a Program is “A Program is a precise sequence of steps” That reflects to the point that when we say that we have a program, it actually means that we know about a complete set of activities to be performed in particular order. The purpose of these activities is to solve a problem that can be complex.

6. W HY P ROGRAMMING IS I MPORTANT Well Programming is very important because of so many reasons; As a CS and IT professionals one must have a broader vision and perspective We cant think like a clerk whose work is just to feed a data. Think about robots, they are programmed, Nuclear Plants they are programmed. Programming is not just only writing a program it is a process that involves critical reading, analytical thinking and creative synthesis

7. W HAT SKILLS ARE NEEDED ? Programming is an important activity as people life and living depends on the programs one make. One should; 1. Paying attention to detail 2. Think about reusability 3. Think about interface 4. Understand the fact that computers are stupid 5. Comment the code liberally

8. H OW TO P ROPERLY DESIGN A PROGRAM Analyze a problem statement, typically expressed as a word problem Express its essence, abstractly and with examples Formulate statements and comments in precise language Evaluate and revise the activities Pay attention to details

9. S OFTWARE C ATEGORIES Software is categorized into two main categories; System Software and Application Software

10. S YSTEM S OFTWARE The system software controls the computer. It communicates with computer’s hardware examples are keyboard, mouse, modem, soundcard etc. and controls different aspects of operations Sub categories of system software are; 1. Operating system 2. Device drivers 3. utilities

11. 1. O PERATING S YSTEM An operating system also abbreviated as OS is the program that manages all the other programs in a computer. It is an integrated collection of routines that service the sequencing and processing of programs by a computer. An operating system may provide many services such as resource allocation, scheduling, I/O Control and data management.

12. 2. D EVICE D RIVERS The device driver software is used to communicate between the devices and the computer. If you go on the Device Manager of your system you will find all the information there. When we attach new device we need to have the software for that, think about when you want to plug in your hand set to your machine you have to install the driver.

13. 3. U TILITY S OFTWARE It is a program that performs a very specific task usually related to managing system resources. You might have noticed the utility of disk compression whenever you write a file and save it to disk. Compression utilities, defragmentation utilities is another example

14. A PPLICATION S OFTWARE A Program or Group of Programs designed for end users. For example a program for Accounting, Payroll, Control System, Guided System for planes, GPS (Global Positioning System). Another application software is being used in vehicles which through satellite determines the geographical position of the vehicle

15. H ISTORY OF C LANGUAGE Developed in Late 60’s and Early 70’s Early stages it was used to design the operating system and compilers. Now it is widely used in academia Many researchers have added their features to this language. It is an open source platform.

16. T OOLS OF THE T RADE As a programmer we need different tools to develop a program. These tools are also developed by programmers. 1. Editor: First of all we need something to write the algorithm. 2. Compiler and Interpreter: As we do write the code in English and we also know that computers don’t know any thing apart 0 and 1. we need a translator for that.

17. T OOLS FOR THE TRADE C ONTINUED 3. Debugger: Another Important tool is Debugger. Every software programmer must know about it. It is used to correct the logical errors. 4. Linker: Most of the time our program is using different routines that are stored in different locations. Linker Links all those files to a common place to make it a standalone and executable code. The process is also called linking.

18. T OOLS FOR TRADE C ONTINUED 5. Loader: After a executable program is linked and saved on a disk and it is ready for execution. We need another process that loads the program into memory, and than instruct the processor to execute the program from the first instruction. The starting point for every C program is from the main function.