Week Five | Java & FTC

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Assignment

In Class Exercise

Methods/Functions summary

Operators

public class WeekFiveEx1 {
    public static void main(String args[]) {

        //Assignment operators
        int x = 2;
        int y = 1;
        int sum = x + y;
        int multiplication = x * y;
        int division = x / y;
        int modulus = x % y;
        System.out.println("Sum :"+sum);
        System.out.println("Multiplication :"+multiplication);
        System.out.println("Division :"+division);
        System.out.println("Modulus :"+modulus);
//        System.out.println(x++);
//        System.out.println(++x);
//        System.out.println(x);

        //Comparison Operators
        System.out.println(x>y);
        System.out.println(x==y);
        System.out.println(x!=y);
        System.out.println(x<y);
    }
}

In Class Exercise

Swap values of x & y and print results (I would recommend creating a new java class for this.)

int x = 20;
int y = 30;

/*
NOTE - THE FOLLOWING WILL NOT WORK, YOU CAN TRY IT THOUGH
x = y;
y = x;

Psuedocode

create a temp variable as below

int temp;

store value of x in temp variable as below

temp = x;

now assign value of x to y as below

x = y;

now assign value of temp to y as below

y = temp;

*/

System.out.println(x); // should print 30;
System.out.println(y); // should print 20;

if..else

if (condition) {
  // block of code to be executed if the condition is true
}

public class WeekFiveEx2 {
    public static void main(String args[]) {

        int x = 2;
        int y = 1;

        if(x > y) {
            System.out.println("x is greater than y");
        }
    }
}

if (condition) {
  // block of code to be executed if the condition is true
} else {
  // block of code to be executed if the condition is false
}

In class exercise Use WeekFiveEx2 as a starting point and add the else clause above to print y is greater than x

Ternary operator

variable = (condition) ? expressionTrue :  expressionFalse;

Example

boolean isXGreaterThanY = (x > y) ? true : false;

Array Data type

Array data types
Exercise below as part of for loop.

for loop

for loop

Print values in array

public class WeekFiveEx3 {
  public static void main(String args[]) {

      int[] numbers = {42, 20, 1, 13};
      System.out.println(numbers[0]);

      for(int i = 0; i < numbers.length; i++) {
          System.out.println(numbers[i]);
      }
  }
}

In class exercise

Find the first index of a word in a sentence.

Example one:

Assume my sentence is: “The Constitutional Convention in Philadelphia met between May and September of 1787 to address the problems of the weak central government that existed under the Articles of Confederation.”

And I want to find the index of the word “Convention” or “convention”, the answer should be 2.

Example two:

Assume my sentence is: “Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.”

And I want to find the index of the word “Liberty” or “liberty”, the answer shoudl be 18.

Mock code

split sentence into a string array. You can use the split method in string, it returns an ayrray of strings.
loop thru the string array check value at each index againt word you are comparing. Use the .equals or .equalsIgnoreCase method to compare strings. Do not use == as it compares memory location and the not word itself.
if word is found, that is the index of the word, you can print the index.

while loop (if we have time.)

while loop

public class WeekFiveEx4 {
    public static void main(String args[]) {
        int i = 0;
        while(i < 10) {
            System.out.println(i);
            i++;
        }
    }
}

Assignment Sort array so highest number is at the end of the array.

Input

int[] numbers = {42, 20, 1, 13};

Iterate over your array after you implement step 1 & 2 and output must be

Number at index 0: 20
Number at index 1: 1
Number at index 2: 13
Number at index 3: 42

STEP 1 - if number at index or i is greater than number at index + 1 or i + 1, print `number at index is greater than number at index + 1 where i is : ……

Sample code

int[] numbers = {42, 20, 1, 13};
for(int i = 0; i < numbers.length -1; i++) { //NOTE LOOK AT MY FINAL CONDITION numbers.length -1
    //if(number[i] > number[i+1]) {
        // print statement -> number at index is greater than number at index + 1 where i is : ......
    // }
   
}

STEP 2 - if number at index or i is greater than number at index + 1 or i + 1 then swap elements at index or i and index + 1 or i +1. Sample code

int[] numbers = {42, 20, 1, 13};
for(int i = 0; i < numbers.length -1; i++) { //NOTE LOOK AT MY FINAL CONDITION numbers.length -1
    //if(number[i] > number[i+1]) {
        // print statement -> number at index is greater than number at index + 1 where i is : ......
        // your swap code here.
        // look at in class exercise to swap numbers
    // }
   
}