Embed Size (px)
Citation preview
CS 152 Professor: Leah Buechley
TAs: Bethany Pena, Kayla Potter, Jared Tredway, Arlin Pedregon Time: MWF 10:00-10:50am
Location: Zoom https://handandmachine.cs.unm.edu/classes/CS152_Fall2020/
Computer Programming Fundamentals
JAVA
open up your GettingStarted.java program from last class
open up Terminal/Command Prompt
navigate to your GettingStarted folder
THE COMMAND LINEJaeren's Handy Reference
MAC• cd = change directory• ls = list folders and
files within a directory• pwd = print the
directory that you’re currently in
PC• cd = change directory• dir = list folders and
files within a directory
THE COMMAND LINE
• up arrow key will go through a history of your previous commands
• use it instead of typing stuff over and over
• the tab key will finish typing a command for you, if that is possible
• use it instead of typing long commands
COMPILE & RUN “GettingStarted.java”COMPILE = javac
RUN = java
COMPILING JAVA PROGRAMS
• Source code written in a .java file• Compiler converts source code into byte
code, a .class file• The Java Virtual Machine (JVM) runs this
byte code, translating it into instructions that your computer executes
use dir or ls to see your .class file
OUR FIBONACCI FUNCTION
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, …Xn = Xn-1 + Xn-2
THE FIBONACCI SEQUENCE
OUR FUNCTION SO FAR (HAS ERRORS)
public static long fibonacci (long input) {long result = 0;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
OUR FUNCTION SO FAR (HAS ERRORS)public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();factorial(number);
}
public static long fibonacci (long input) {long result = 0;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
OUR FUNCTION SO FAR (HAS ERRORS)public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();System.out.println(fibonacci(number));
}
public static long fibonacci (long input) {long result = 0;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
save, compile, and run
OUR FUNCTION SO FAR (HAS ERRORS)public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();System.out.println(fibonacci(number));
}
public static long fibonacci (long input) {long result = 0;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
OUR FUNCTION SO FAR (HAS ERRORS)public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();System.out.println(fibonacci(number));
}
public static long fibonacci (long input) {long result = input;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
save, compile, and run
ADD A FOR LOOP TO PRINT THE SEQUENCEpublic static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();for (int i=0; i<number; i++) {
}}
public static long fibonacci (long input) {long result = input;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
ADD A FOR LOOP TO PRINT THE SEQUENCEpublic static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();for (int i=0; i<number; i++) {
System.out.print(fibonacci(i) + ", ");}
}
public static long fibonacci (long input) {long result = input;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
ADD A FOR LOOP TO PRINT THE SEQUENCEpublic static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Type in a number:");int number = sc.nextInt();for (int i=0; i<number; i++) {
System.out.print(fibonacci(i) + ", ");}
System.out.println(fibonacci(number));}
public static long fibonacci (long input) {long result = input;
if (input == 1 | input == 0)return result;
else {result = fibonacci(input - 1) + fibonacci(input - 2);return result;
}
}
FIBONACCI SPIRAL
More info: https://www.mathsisfun.com/numbers/nature-golden-ratio-fibonacci.html
STRINGS
create a new program “LetterCount.java”save it in a folder called LetterCount
LETTER COUNTclass LetterCount {
}
programwill prompt you to enter a wordwill prompt you to enter a letter
will count the number of times the letter appears in the word and print out the count
will use the Scanner class again
LETTER COUNTimport java.util.Scanner;
class LetterCount {
}
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {
}
}
Java reference: https://docs.oracle.com/en/java/javase/15/ other references: https://www.w3schools.com/java/default.asp
+ google is your friend!
HOW TO GET HELP
prompt for a word
how do we read a word from the Scanner?
good reference for Scanner: https://www.w3schools.com/java/java_user_input.asp
good reference for Strings:https://www.w3schools.com/java/java_ref_string.asp
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(System.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
}
}
save, compile, and runin general, save and compile often
prompt for a letter
how do we read a letter from the Scanner?
good reference for Scanner: https://www.w3schools.com/java/java_user_input.asp
good reference for Strings:https://www.w3schools.com/java/java_ref_string.asp
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(system.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
//ask for a letterSystem.out.println("Type in a letter:");char letter = sc.next().charAt(0);
}
}
save, compile, and run
count number of times letter appears in word
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(System.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
//ask for a letterSystem.out.println("Type in a letter:");char letter = sc.next().charAt(0);
//search through the entire word int count = 0;
for (int i = 0; i<word.length(); i++) {
}}
}
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(System.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
//ask for a letterSystem.out.println("Type in a letter:");char letter = sc.next().charAt(0);
//search through the entire word int count = 0;
for (int i = 0; i<word.length(); i++) {if (word.charAt(i) == letter)
count++;}
}
}
print out the count
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(System.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
//ask for a letterSystem.out.println("Type in a letter:");char letter = sc.next().charAt(0);
//search through the entire word int count = 0;
for (int i = 0; i<word.length(); i++) {if (word.charAt(i) == letter)
count++;}
//print out the countSystem.out.println(word +" has " +count +" " +letter +"'s.");
}
}
LETTER COUNTimport java.util.Scanner;
class LetterCount {
public static void main(String[] args) {Scanner sc = new Scanner(System.in);
//ask for a wordSystem.out.println("Type in a word:");String word = sc.next();
//ask for a letterSystem.out.println("Type in a letter:");char letter = sc.next().charAt(0);
//search through the entire word int count = 0;
for (int i = 0; i<word.length(); i++) {if (word.charAt(i) == letter)
count++;}
//print out the countif (count == 0)
System.out.println(word +" has no " +letter +"'s.");else if (count == 1)
System.out.println(word +" has 1 " +letter +".");else
System.out.println(word +" has " +count +" " +letter +"'s.");}
}
questions?
CS 152 Professor: Leah Buechley
TAs: Bethany Pena, Kayla Potter, Jared Tredway, Arlin Pedregon Time: MWF 10:00-10:50am
Location: Zoom https://handandmachine.cs.unm.edu/classes/CS152_Fall2020/
Computer Programming Fundamentals
