CSC305: COMPUTER PROGRAMMING II (JAVA) AJAYI, O. O. ajjavax@gmail.com

INTRODUCTION Intro to JAVA as an Object-Oriented Programming Language. Intro the Structure of Java Intro to Data Types in Java Intro to Java I/O Statements

INPUT Statement The NEEDFUL… …using SCANNER IMPORT TEMPORAL Scanner ASSIGNMENT

ILLUSTRATION Write a Java program that accepts values for two integer variables and compute their summation.

STEPS & SOLUTION STEPS… Click FILE  NEW PROJECT Under CATEGORY, select JAVA Under PROJECT, select JAVA APPLICATION Click NEXT Under PROJECT NAME, specify your desired name If needful, specify the directory for storing/saving your file OR use the default Click FINISHED

The look… Depending on your IDE type, you should be having something like this now… package mywork1; public class Mywork1 { public static void main(String[] args) { ……TODO – your coding goes here }

NEXT… Note however, your IMPORT Statement package mywork1; import java.util.Scanner; public class Mywork1 { public static void main(String[] args) { ……TODO – your coding goes here }

Gradual Coding now- Illustration I/O Statements in Java import java.util.Scanner; //under package… Public class………..{ Public static void main (String args[]){ int a,b,sum; Scanner getin = new Scanner (System.in); System.out.print(“Input me: ”); a = getin.nextInt(); System.out.print(“Input the other: ”); b = getin.nextInt(); sum = a+b; System.out.printf(“The summation of a and b is %d”, sum); }

I/O Statement cont’d I/O Statements in Java GUI Method Steps: Import the JOptionPane using javax.swing.JOptionPane; Access the GUI either for: Inputting (showInputDialog…….), OR Outputting (showMessageDialog……)

Illustration I: A Java Program to capture and welcome user’s ID public class ……….. { public static void main(String[] args) { String username; username = JOptionPane.showInputDialog("Enter Username: "); JOptionPane.showMessageDialog(null, "Welcome " +username, "AJ App", JOptionPane.ERROR_MESSAGE); }

Illustration II: A Java Program to capture values for two integers (using GUI) and then compute their summation; OUTPUTTING it (i) on console (ii) via GUI import java.util.Scanner; import javax.swing.JOptionPane; public class Mywork1 { public static void main(String[] args) { int a, b,sum; String a2, b2; a2 = JOptionPane.showInputDialog("Enter 1st No:"); b2 = JOptionPane.showInputDialog("Enter 2nd No:"); a = Integer.parseInt(a2); b = Integer.parseInt(b2); sum = a+b; System.out.printf("The sum is: %d", sum); }

Illustration II: OPTION II import java.util.Scanner; import javax.swing.JOptionPane; public class Mywork1 { public static void main(String[] args) { int a, b,sum; String a2, b2; a2 = JOptionPane.showInputDialog("Enter 1st No:"); b2 = JOptionPane.showInputDialog("Enter 2nd No:"); a = Integer.parseInt(a2); b = Integer.parseInt(b2); sum = a+b; JOptionPane.showMessageDialog(null,"The sum total is" +sum, "AJ APP", JOptionPane.INFORMATION_MESSAGE); }

Weekend Practical Activities Write a simple Java program that demonstrate the differences between PRINT, PRINTLN and PRINF Statements. Aside +, -, *, / which are common arithmetic operators in Java and other programming languages, Java also has % for modulus computation. With this and with your knowledge of iterative statement like do-while, while & for statement, write a Java program that converts 5710 to base 2. We would soon get to the chapter that deals with Control Statement. But I can tell you it’s the same as in C++. Review the use of Switch Statement in C++ and deploy the knowledge to write a PHONE BATTERY STATUS program such that when the battery power % is >=70 u report ‘battery can carry thru to the desert’, <70 but >29, ‘be moving close to power source’, <30 but >19, ‘am weak & thirsty for refilling’, <20 but >4, ‘I will soon disappoint u’, else ‘u succeeded in killing me, wicked owner’.