Cs 1114 - lecture-3
Download as PPT, PDF•0 likes•375 views
The document discusses programming fundamentals and decision making in programs. It provides examples of programs that calculate simple tasks like area of a rectangle and difference between two numbers. It then explains how decision boxes allow programs to make decisions based on conditions, like checking if a difference is positive or negative. Decision making allows programs to solve more complex problems by performing comparisons and branching execution. Keywords like "if", "whether" indicate when decision making is required to solve a problem.
Cs 1114 - lecture-3
- 2. Tasks (from previous lecture) Calculate area of a rectangle area = base height Find Cube of a Number Calculate Marks Percentage (marks obtained / total marks) 100 Calculate Sales Tax amount (tax percent / 100) Find “no. of minutes” and “no. of seconds” for given “no of years” Programming Fundamentals | Lecture-3
- 3. Power of Computer Programs Once given the input They perform the instructions (or no. of steps as instructed by the programmer) themselves and give the desired output No matter how complex the problem is and how long they have to work on it Programming Fundamentals | Lecture-3 Now We Will Further Explore Their Power
- 4. Consider this Problem Find absolute value after subtracting one number from another Difference = number1 – number2 Programming Fundamentals | Lecture-3
- 5. Difference of Two numbers Programming Fundamentals | Lecture-3 START READ number1, number2 difference = number1 - number2 DISPLAY difference STOP Will result in a negative value if number1 is smaller than number2
- 6. Is This Solution Correct? Programming Fundamentals | Lecture-3 START READ number1, number2 difference = number1 - number2 DISPLAY difference STOP difference = difference * -1
- 7. Analyze the Problem There exists two conditions Condition-1 Difference is positive Condition-2 Difference is negative Programming Fundamentals | Lecture-3
- 8. What is to be Done? There exists two conditions Condition-1 Difference is positive Do not do any conversion, because value is already positive Condition-2 Difference is negative Convert it into a positive value by multiplying it by “-1” Programming Fundamentals | Lecture-3
- 9. Should we design two different solutions? Programming Fundamentals | Lecture-1
- 10. What is Required? Need to design a solution in such a way which can decide for itself whether to multiply the difference by “-1” or not (by checking the value of difference) The graphical shapes which we have learned so far are insufficient to provide this kind of “ decision making ” Programming Fundamentals | Lecture-3
- 11. Decision Box Programming Fundamentals | Lecture-3 Decision Rule Yes No Always in the form whose answer is “ Yes” or “No”
- 12. Programming Fundamentals | Lecture-3 START READ number1, number2 difference = number1 - number2 DISPLAY difference STOP difference = difference * -1 difference < 0 Yes No
- 13. Power of Computers Decision Making Programmers can instruct computers to make decisions while solving a problem As the complexity of problems increases, decision making process become more extensive This way computers prove very useful by performing laborious tasks of decision making Programming Fundamentals | Lecture-3
- 14. Another Example Find smaller of two numbers Input number1 number2 Output smaller Processing Compare the numbers with each other and decide which one is smaller Programming Fundamentals | Lecture-3
- 15. Programming Fundamentals | Lecture-3 START READ number1, number2 DISPLAY smaller STOP smaller = number1 number1 < number2 Yes No smaller = number2
- 16. Alternative Programming Fundamentals | Lecture-3 START READ number1, number2 STOP DISPLAY number1 number1 < number2 Yes No DISPLAY number2
- 17. Comparison Operators < (less than) > (greater than) <= (less than equal to) >= (greater than equal to) == (equal to) != (not equal to) Programming Fundamentals | Lecture-3
- 18. Output a Message Programming Fundamentals | Lecture-3 DISPLAY “This is a message”
- 19. Try it Yourself Find whether a number is negative or not? Find whether two numbers are equal or not? Multiply two numbers if their difference is greater than 0 Programming Fundamentals | Lecture-3
- 20. Some Keywords Look for these keywords in problem statement in order to determine the usage of decision box If If and only if Whether Programming Fundamentals | Lecture-3
- 21. Tasks (to be done by next lecture) Find whether the sum of two numbers is greater than 50 Find whether the sum of two numbers is greater than the third number? Divide a number by another if only if the second number is not equal to “0” Determine whether a student is “passed” or “failed” from his marks A student securing marks less than 50 is considered “failed” Programming Fundamentals | Lecture-3
- 22. Programming Fundamentals | Lecture-2 BE PREPARED FOR QUIZ IN NEXT LECTURE