Exercise operator

src/examples/casting/NarrowingConversion.java

@@ -0,0 +1,15 @@
+package examples.casting;
+
+public class NarrowingConversion {
+    public static void main(String[] args) {
+        double x = 10.23;
+        System.out.println("x " + x);
+        int z = (int) x;
+        System.out.println("z " + z);
+        double d = 100.04;
+        long l = (long)d;
+        int i = (int)l;
+        System.out.println("long value " + l);
+        System.out.println("Int value " + i);
+    }
+}

src/examples/casting/WideningConversion.java

@@ -0,0 +1,15 @@
+package examples.casting;
+
+public class WideningConversion {
+    public static void main (String[] args){
+        int i = 100;
+        long l = i;
+        float f = l;
+        double x = f;
+        System.out.println("int value " + i);
+        System.out.println("long value " + l);
+        System.out.println("float value " + f);
+        System.out.println("double value " + x);
+    }
+
+}

src/labs_examples/datatypes_operators/labs/Exercise_01.java

@@ -16,7 +16,15 @@ public class Exercise_01 {
 
     public static void main(String[] args) {
 
-        // write code here
+        int a = 4;
+        double b = 6.8;
+        float c = 3.5f;
+        char d = 'd';
+
+        System.out.println("int a = " + a);
+        System.out.println("double b = " + b);
+        System.out.println("float c = " + c);
+        System.out.println("char d = " + d);
 
     }
 }

src/labs_examples/datatypes_operators/labs/Exercise_02.java

@@ -23,7 +23,12 @@ public class Exercise_02 {
 
     public static void main(String[] args) {
 
-        // write code here
+        int a = 10;
+        double b = a;
+        System.out.println("double b = " + b);
+        double c = 10.5;
+        int d = (int) c;
+        System.out.println("int d = " + d);
 
     }
 }

src/labs_examples/datatypes_operators/labs/Exercise_03.java

@@ -9,8 +9,17 @@
 class ArithmeticOperators {
 
     public static void main(String[] args) {
+        int a = 2 + 3;
+        double b = 3.5- 2.8;
+        double c = 2.3 * 3.4;
+        double d = 8 / 3;
+        int e = 7 % 3;
 
-        // write your code below
+    System.out.println("after addition " + a);
+    System.out.println("After subtraction " + b);
+    System.out.println("After multiplication " + c);
+    System.out.println("After division " + d);
+    System.out.println("After modulus " + e);
 
     }
 

src/labs_examples/datatypes_operators/labs/Exercise_04.java

@@ -15,6 +15,14 @@ public static void main(String[] args) {
         int b = 2;
         if (a < b){
             System.out.println("a is less than b");
+        } if(b > a){
+            System.out.println("b is greater than a");
+        }if( a == b){
+            System.out.println("a is equals to b");
+        }if(a <= b ){
+            System.out.println("a is less than b or a is equals to b");
+        }if( b >= a){
+            System.out.println("b is greater than a or b is equals to a");
         }
 
         // write your code below

src/labs_examples/datatypes_operators/labs/Exercise_05.java

@@ -15,6 +15,16 @@ public static void main(String[] args) {
         boolean b = false;
         if (a | b){
             System.out.println("a or b is true");
+        }if (a || b){
+            System.out.println("if a is true then check b");
+        }if(a & b){
+            System.out.println("a and b both are true");
+        }if (a && b){
+            System.out.println("both are true");
+        }if (a ^ b){
+            System.out.println("a and b are different");
+        }if (a != b){
+            System.out.println("a not equals to b");
         }
 
         // write your code below

src/labs_examples/datatypes_operators/labs/Exercise_06.java

@@ -12,7 +12,11 @@ public class Exercise_06 {
 
     public static void main(String[] args) {
 
-        // write code here
-
+        double r = 3.14;
+        double h = 5;
+        double volume = 3.14 * r * r * h;
+        System.out.println("the volume of cylinder is " + volume);
+        double surface = 2 * 3.14 * r * h + 2 * 3.14 * r * r;
+        System.out.println("the surface of the cylinder " + surface);
     }
 }

src/labs_examples/datatypes_operators/labs/Exercise_07.java

@@ -16,14 +16,15 @@ public class Exercise_07 {
 
     public static void main(String[] args) {
 
-        // create scanner
+
         Scanner scanner = new Scanner(System.in);
-        // prompt user
+
         System.out.print("Enter a number in days between 1 and 1,000,000: ");
-        // assign input to variable as int
+
         int days = scanner.nextInt();
 
-        // write completed code here
+       long second = days * 24 * 60 * 60;
+       System.out.println("the total seconds of " + days + " are " + second);
 
     }
 }

src/labs_examples/fundamentals/labs/Exercise_03.java

@@ -15,9 +15,7 @@ public class Exercise_03 {
     public static void main(String[] args) {
 
         System.out.println("Hello World!");
-
-        // write code to print out "Check out my first program!" below
-
+        System.out.println("Check out my first program!");
     }
 
 }

src/labs_examples/fundamentals/labs/Exercise_04.java

@@ -15,7 +15,27 @@ public static void main(String[] args) {
         int i = 1;
         System.out.println("int i is: " + i);
 
-        // write your code below
+        byte j = 5;
+        System.out.println("byte j is: " + j);
+
+        long k = 56789;
+        System.out.println("long k is: " + k);
+
+        float l = 7.8f;
+        System.out.println("float l is: " + l);
+
+        double m = 234.987;
+        System.out.println("double m is: " + m);
+
+        char n = 'c';
+        System.out.println("char n is: " + n);
+
+        short o = 8;
+        System.out.println("short o is: " + o);
+
+        String p = "ani";
+        System.out.println("String p is: " + p);
+
 
     }
 

src/labs_examples/fundamentals/labs/Exercise_05.java

@@ -13,15 +13,27 @@ public class Exercise_05 {
     public static void main(String[] args) {
 
         String str = "hello!";
-        // please declare an int variable below, and set it to the value of the length of "str"
+        int length = str.length();
+        System.out.println("the length of string is: " + str);
 
         String str2 = "hello";
-        // please initialize a boolean variable and test whether str is equal to str2
+        boolean equal = str.equalsIgnoreCase(str2);
+        System.out.println("str and str2 is equal: " + equal);
 
-        // please concatenate str & str2 and set the result to a new String variable below
+        String concat = str.concat(str2);
+        System.out.println("concatenate str & str2: " + concat);
+
+        String replace = str.replace('!','?');
+        System.out.println("the new string is: " + replace);
+
+        String sub = str.substring(1,4);
+        System.out.println("the substring is: " + sub);
+
+        Boolean contain = str.contains("ll");
+        System.out.println("Is str contain ll: " + contain);
+
+        System.out.println("the index of str of ello: " + str.indexOf("ello"));
 
-        // please demonstrate the use of any other method that is available to us in the String class
-        // for example, replace(), substring(), contains(), indexOf() etc
 
     }
 

src/labs_examples/variables/Person.java

@@ -0,0 +1,22 @@
+package labs_examples.variables;
+
+public class Person {
+    String name;
+    int age;
+    static int numPersonsCreated;
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+        numPersonsCreated ++;
+    }
+
+    @Override
+    public String toString() {
+        return "Person{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                ",numPersonsCreated=" + numPersonsCreated +
+                '}';
+    }
+}

src/labs_examples/variables/Variables.java

@@ -0,0 +1,23 @@
+package labs_examples.variables;
+
+public class Variables {
+   static double val = 123.45;
+    public static void main(String[] args){
+        Person myPerson = new Person("Rayan", 35);
+        Person yourPerson = new Person("someCoolName", 39);
+        Person einstien = new Person("Einstein", 110);
+        System.out.println(myPerson.toString());
+        System.out.println(yourPerson.toString());
+        System.out.println(einstien.toString());
+      // double x =  multiply(val,val * 2);
+    }
+    public static double multiply(double a, double b){
+       double result = a * b;
+        printNum(result);
+        return result;
+    }
+    public static void printNum(double numToPrint){
+        System.out.println(numToPrint);
+        System.out.println(val);
+    }
+}