1. COMS W1004 Introduction to Computer Science and Programming in Java
Columbia University Fall 2018

2. Lecture 1: Introduction
Course objectives
Course information
Textbooks
Syllabus
Assignments and Grading
Academic Honesty
Preliminary Definitions
Linear Search
Pseudocode
Reading

3. Course Objectives Java programming Skills
Knowledge of the fundamental concepts in computer science
Algorithmic problem solving capabilities

4. Course Information Course website: www.cs.columbia.edu/~cannon/1004/
Course information may be found on courseworks at:
courseworks.columbia.edu
Please look there for answers to your questions
and make use of the Piazza discussion board.

5. Preliminary Definitions
Algorithm:
Dictionary Definition: A procedure for solving a mathematical
problem in a finite number of steps that frequently involves
repetition of an operation; broadly: a step-by-step method of
accomplishing some task.

6. Preliminary Definitions
Algorithm:
Textbook Definition: A well-ordered collection of
unambiguous and effectively computable operations
that when executed produces a result and halts in a finite
amount of time.

7. Preliminary Definitions
Computer Science
Textbook Definition: The study of algorithms including
Their formal and mathematical properties
Their hardware realizations
Their linguistic realizations
Their applications

8. Your first Algorithm Linear Search: (also called sequential search)
Algorithm to determine whether a given name x appears
on a list.
Input: A list of n ≥1 names A[1], A[2], ... , A[n],
and a given name x.
Output. The message "Sorry, x is not on the list" if x is not
on the list.
Otherwise, the message: "x occurs at position i on the list."

9. Pseudocode
A programming language is a notation for specifying instructions that a computer can execute
Every (programming) language has a syntax and a semantics
Syntax specifies how something is said (grammar)
Semantics specifies what it means
Pseudocode is an informal programming language with English-like constructs modeled to look like statements in a Java-like language
Anyone able to program in any computer language should understand how to read pseudocode instructions.
When in doubt just write it out in English.

10. Your first Algorithm
Here are the instructions for linear search written in pseudocode:
found = "no";
i=1;
while (found == "no" and i <= n) {
if (A[i] == x)
{ found = "yes";
location = i; }
i++;
if (found == "no")
print ("Sorry, " + x + " is not on the list");
else
{ print (x + " occurs at position " + location +
" on the list");

11. Reading
Chapters 1 and 2 in Schneider and Gersting