introduction to programming
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Introduction to Programming
Doman’s LectureCSCI101
Method or interface to do this:PROGRAMMING LANGUAGESExample: Java:
Public class helloWorld {Public static void main ( ) {system.out.println(“Hello World”) }}
Instruct a computer
Example: C++ #include<iostream>using namespace std;
int main(){cout << “Hello World” << endl;}
Instruct a computer
Example: html
<html><body><p> Hello World </p></body></html>
Instruct a computer
Example Python
print “Hello World!”
Instruct a computer
Programming is a creative process done by programmers to instruct a computer on how to do a task. (http://cplus.about.com)
What is programming?
Puzzles
Problem solving
What is programming?
Your car has blue smoke coming from the tailpipe, is idling roughly and has lost fuel efficiency.
How do you solve it?
Problem Solving
Unbreakable rules about problems or the way in which problems must be solved.
Car problem constraints: Cost of repair How long before you need it fixed No new tools be purchases
Constraints
Programming language Platform Performance Memory footprint
User/customer specific constraints Design constraints.
Common Programming Constraints
Figure out the steps to take to solve the problem
Be able to list the steps Be able to repeat the steps
You can NOT change the rules (constraints) to get something solved!
Problem solving
PROBLEM: HOW TO CROSS THE RIVER?
A farmer with a fox, a goose and a sack of corn needs to cross a river. The farmer has a rowboat, but there is only room for the farmer and one of his three items. Unfortunately, both the fox and the goose are hungry. The fox cannot be left alone with the goose; the goose cannot be left alone with the grain. How does the farmer get everything across the river?
Puzzle: Fox, goose, grain
Constraints Only one item at a time in the boat Can’t leave fox with goose Can’t leave goose with grain
Operations Carry the fox to the far side of the river Carry the goose to the far side of the river Carry the grain to the far side of the river
Puzzle: Fox, goose, grain
An association between a value and a symbolic name
Sentence = “Hello World!” Print Sentence
Variables
Like a recipe or a blueprint
A repeatable set of instructions that tell the computer to do something to reach a goal.
Algorithm
Abstract the problem Be more general in describing the way we
will solve the problem
Concept: VariableVariable is the item that can goes into the boat: fox, goose or grainLet item vary between fox, goose or grain
Rephrase the problem
Puzzle: Fox, goose, grain
Constraints Only one item at a time in the boat Can’t leave item(fox) with item(goose) Can’t leave item(goose) with item(grain)
Operations Row the boat from one shore to the other If the boat is empty, load an item on the boat If the boat is full, take the item off the boat
Puzzle: Fox, goose, grain
Puzzle: Fox, goose, grain
Puzzle: Sudoku
3 4 78 16 2 5
5 8
4 7
1 97 3
3 4 78 9 16 2 5
Constraints
Techniques Start with the easiest Try something…… be prepared to change if it doesn’t work. Try something else
Puzzle: Soduko
Problem Solving Have a plan Generalize the problem
Restate the problem Start with what you know Divide the problem Look for analogies or patterns Experiment!!!
THINK like a programmer!
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