CSCI N 201 Programming Concepts and Database 8

CSCI N 201 Programming Concepts and Database 8 – Conditions Lingma Acheson linglu@iupui. edu Department of Computer and Information Science, IUPUI 1

Task: • Ask the user to input a required integer, and compare the input to the required integer. If it’s the same, output “You entered the right integer!” If not the same, no output. • E. g. – Comp: Please enter integer 9: User: 9 Comp: “You entered the right integer!”

Algorithm Design • Pseudocode – a mixture of natural language with programming language to help in algorithm design. • Algorithm design: - Start a new program - Create a new variable n 1 - Prompt for user input “Please enter integer 9: ” and store the input to n 1 - Change n 1 to integer - If n 1=9, output “You entered the right integer!” - End the program

Using Miracle • http: //www. cs. iupui. edu/~aharris/Mir. JS. ht ml • Begin the If branch (Conditional => If branch) • Give the two numbers or values to compare • Give the comparison operator – – – == != <= >= < > Equals Not Equal Less than or equal to Greater than or equal to Less than Greater than • End the If branch (Conditional => End structure)

If Statement • • Checks a condition Begins a block of code If condition is true, executes all codes in block If condition is false, skips code block

Refine the Algorithm • Pseudocode: - Start a new program - Create a new variable n 1 - Prompt for user input “Please enter integer 9: ” and store the input to n 1 - Change n 1 to integer - If n 1==9, output “You entered the right integer!” - End if - End the program • Using Miracle!

Else Branch • If the user input is not 9, output “You entered a wrong integer!” • Pseudocode: - Start a new program - Create a new variable n 1 - Prompt for user input “Please enter integer 9: ” and store the input to n 1 - Change n 1 to integer - If n 1==9 output “You entered the right integer!” else output “You entered a wrong integer!” - End if - End the program

Else Clause • Else is a useful addition to If statements. • Else allows you to set up another block of code to execute if the condition is false • Using Miracle!

Lab • Create a program to compare two user inputs and output the comparison result. • Extra 20 credit: – Create a program to take two integers, ask the user to enter “+”, “ -”, “*”, or “/”. Perform the correspondent maths operation and output the result to the user.