1-1 Logic and Syntax A computer program is a solution to a problem. An algorithm is the logical design used to accomplish a specific objective. The Visual Logic Development System combines the utility of flowcharts and pseudocode with computer simulation.
1-1 Logic and Syntax (cont.) Syntax refers to the specific rules of a programming language. An information system is a combination of people and technology that collect, organize, and process data to produce information.
1-1 Logic and Syntax (cont.) An information system must do at least three things: input data into the system process data within the system output resulting information from the system
1-2 “Hello World”
1-2 “Hello World” (cont.)
1-2 “Hello World” (cont.)
1-3 Input Statements An input statement accepts data from the user and stores that data into a variable. A variable is a storage location that can be accessed and changed by developer code.
1-3 Input Statements (cont.)
1-3 Input Statements (cont.)
Simple Programming Formats
1-4 Weekly Paycheck Program The weekly paycheck program has two input variables: Hours and Rate
1-5 Assignment Statements The assignment statement can be used to perform a calculation and store the result. An expression is a value-returning code element, such as a variable or mathematical formula.
How to Write Arithmetic Expressions
How to Write Arithmetic Expressions (cont.)
Types of output include 1-6 Output Statements Types of output include Screen output Printed output Sound output Saving to storage devices
1-6 Output Statements (cont.)
1-6 Output Statements (cont.)
Intrinsic Functions Intrinsic functions are predefined commands that provide developers with common, helpful functionality.
Intrinsic Functions (cont.)
1-7 Debugging with Visual Logic A programming mistake is often called a bug.
Chapter Summary Variables are storage locations used for holding input and processing information. Each variable has two components: its name and its value. Input statements are used to get data into variables. Expressions are value-returning code elements.
Chapter Summary (cont.) Assignment statements are used to perform calculations and store the result. Output statements are used to display information. Input, assignment, and output statements are sufficient to write small programs.