Notes

//question 0

//write hello world program
// execute the program on the terminal
public class exercise_0 {
public static void main(String[] args) {
//hint System.out.println method
System.out.print("hello worldt");
System.out.println("hello world");
}

}

//question 1

/*
Write a Java program that declares three variables: an int, a double, and a String.
Assign values to these variables and print statements that include these variables.
Hint:
- use println snd string concatenation (+) when writing the statements.
or
- use printf when printing the statements.

*/

/**
* exercise_1
*/
public class exercise_1 {

public static void main(String[] args) {
int a = 10;
double b = 10.545;
String c = "Java";


System.out.println("The value of a is: " + a);
System.out.println("The value of b is : " + b);
System.out.println("The value of c is: " + c);


//use println use format such as "The value of a is: " + a
/*

* the output of print
* The value of a is: 10
* The value of b is: 10.545
* The value of c is: Java
*/
System.out.printf("The value of a is : %dn" ,a);
System.out.printf("The value of b is: %.2fn", b);
System.out.printf("The value of c is: %s ",c );

//use printf + %d for integer, %f for float, %s for string + n for new line
/*
* the output of print
* The value of a is: 10
* The value of b is: 10.55
* The value of c is: Java
*/

}
}

//question 2
my PC is Mac, so forward slash is working
/*
* write a program that prints out the following path:
* "C:newfoldertreefile.txt"
* Note: you can use the escape character '' to print out the backslash character ''
*/
public class exercise_2 {

public static void main(String[] args) {
//print the path: C:newfoldertreefile.txt
System.out.println("C:/newfolder/tree/file.txt");
}

}

//question 3
/**
* exercise_3: printf and String.format comparison
*/
public class exercise_3 {

public static void main(String[] args) {

String a = "John";
double b = 25;
String c = "Java";

//use format string
String introductionTemplate = """
Hello, my name is %s.
I am %.0f years old.
My favorite programming language is %s.
""";


//using printf
System.out.printf(introductionTemplate, a, b, c);

//Using String.format
String introduction = String.format(introductionTemplate, a, b, c);
System.out.println(introduction);
//or
System.out.println(String.format(introductionTemplate, a, b, c));
}
}

//question 4

// declare and assing string variable
// use some method such as print the length of the string
// change it to uppercase
public class exercise_4 {
public static void main(String[] args) {
String a = "John";
int length= a.length();
System.out.println("THE LENGTH OF THE STRING IS " + length);

//print the length of the string
//hint call the length() method on the string

//print the string in uppercase
//hint call the toUpperCase() method on the string
}
}

//question 5
/*
* Generate a random number between 1 and 100.
* format it to be shown with two decimal places.
* If the number is even, print the formatted number. If the number is odd, print "Odd".
*/
public class exercise_5 {
public static void main(String[] args) {
double random = 0;
for (int i = 0; i < 100; i++) {
//generate a random number between 1 and 100 and assign it to the variable random
// hint: use Math.random() to generate a random number between 0 and 1
//format the number to two decimal places
random = Math.random() * 100;
// Change the type of the random to integer
int randomInt = (int) random;
//if the number is even, print the formatted number.
//If the number is odd, print "Odd".
if (randomInt % 2 == 0) {
//print the formatted number
System.out.println(randomInt);
} else {
//print "Odd"
System.out.println("Odd");
}
}
}
}