1. Programming Languages V22.0002 Deena Engel’s class

2. Programming languages and Natural Languages They both use: syntax (e.g. punctuation) grammar (“well formed sentences”) parts of speech (reserved words) semantics (meanings of variables, objects similar to pronouns)

3. Natural Languages use: Syntax: punctuation and spacing Grammar: to create “well formed sentences” (e.g. subject-verb-object) Parts of speech: nouns, verbs, adjectives Semantics: the meaning of the words and what they represent (e.g. in English, “cat” refers to a furry, four-pawed mammal in the Great Cats family)

4. Programming Languages use: Syntax: punctuation such as parentheses, braces, brackets, semicolons, etc Grammar: well-formed structures such as “for loops” and others Parts of speech: different data types such as integers, characters, dates Semantics: the meaning of the symbols, e.g. x = 3; or the use of reserved words.

5. Writing Steps in writing code in a programming language: Source code  Compiler  Machine language

6. Style Style counts … in both kinds of languages! In natural language … style distinguishes the type of writing e.g. the differences between a sonnet by Shakespeare and my weekly shopping list… In a programming language, style is both important to make the program readable and in terms of efficiency

7. How to use programming languages: Natural languages: can be used to tell a story … and other purposes … as well as to give instructions. Cookbooks and how-to books provide instructions in a natural language: “mix ½ cup of sugar into the butter” The instructions might include decisions: “if these are chocolate chip cookies, add chocolate chips and shredded coconut ; otherwise just add shredded coconut”).

8. Programming Languages... Give instructions to the computer! A computer program is like a cookie recipe except that the computer follows the instructions!

9. Programming Languages give instructions: Any series of repeated instructions can be called an algorithm. In many cases, the programming language mirrors what you would do if you were doing the task manually: Keeping a checkbook: order the amounts by the date of the check; if it’s a check, subtract the amount; if it’s a deposit, add the amount; then print the running total Create an index for a textbook: read the text; discard extra words (“the”, “and”); list the important terms and their pages; write it up as an index

10. Storing Data Programming languages are also used to track information in logical ways: For example, one can write a program to creating a database of names, addresses and telephone numbers. We will look at this means of expression as well.