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collectionsframework completed #11

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51 changes: 47 additions & 4 deletions src/main/java/Collections/Practice/CollectionBasics.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2,14 +2,16 @@

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

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

Collection<Integer> numbers = new ArrayList<>();

filterGreaterThanTwenty(numbers);
numbers.add(4);
numbers.add(4);
numbers.add(8);
numbers.add(15);
numbers.add(16);
numbers.add(23);
Expand All @@ -29,6 +31,10 @@ public static void main(String[] args) {
public static int sum(Collection<Integer> numbers) {

int total = 0;
for (int i: numbers){
total+=i;
}


// TODO:
// Loop through the collection
Expand All @@ -45,6 +51,12 @@ public static int sum(Collection<Integer> numbers) {
public static int countEven(Collection<Integer> numbers) {

int count = 0;
for (int i = 0; i<=numbers.size(); ++i){
if (i %2==0){
count++;
System.out.println(count);
}
}

// TODO:
// Loop through the collection
Expand All @@ -61,6 +73,13 @@ public static int countEven(Collection<Integer> numbers) {
public static int findMax(Collection<Integer> numbers) {

int max = Integer.MIN_VALUE;
for (int num: numbers){
if (max < num){
max= num;
}else {
max = Integer.MIN_VALUE;
}
}

// TODO:
// Loop through numbers
Expand All @@ -80,6 +99,22 @@ public static boolean hasDuplicates(Collection<Integer> numbers) {
// TODO:
// Hint:
// Compare the size of a collection with the size of a Set
Set<Integer> numbersset= new HashSet<>();
numbersset.add(4);
numbersset.add(4);
numbersset.add(15);
numbersset.add(16);
numbersset.add(23);
numbersset.add(42);

for (int i = 0; i< numbers.size();++i){
for (int e = 0; e < numbersset.size(); ++i ){
if (i==e){
return true;
}
}

}

return false;
}
Expand All @@ -96,6 +131,9 @@ public static int countOccurrences(Collection<Integer> numbers, int target) {
// TODO:
// Loop through numbers
// If number equals target, increase count
for (int i=0; i==target; ++i){
++count;
}

return count;
}
Expand All @@ -109,11 +147,16 @@ public static int countOccurrences(Collection<Integer> numbers, int target) {
public static Collection<Integer> filterGreaterThanTwenty(Collection<Integer> numbers) {

Collection<Integer> result = new ArrayList<>();

for (int num:numbers){
if (num>20){
result.add(num);
}
}
// TODO:
// Loop through numbers
// Add numbers greater than 20 to result

System.out.println(result);
return result;

}
}
22 changes: 16 additions & 6 deletions src/main/java/Collections/Practice/CommonMethodsDemo.java
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Original file line number Diff line number Diff line change
Expand Up @@ -131,31 +131,41 @@ public static void main(String[] args) {
Add the following values:
10, 20, 30, 40, 50
*/

Collection<Integer> numbers = new ArrayList<>();
numbers.add(10);
numbers.add(20);
numbers.add(30);
numbers.add(40);
numbers.add(50);

/*
TODO 2:
Print the size of the numbers collection
*/

System.out.println(numbers.size());

/*
TODO 3:
Check if the collection contains 30
*/


if (numbers.contains(30)){
System.out.println("thirty is here");
}else {
System.out.println("no thirty here");
}
/*
TODO 4:
Remove the number 20
*/

numbers.remove(20);

/*
TODO 5:
Loop through the numbers collection
and print each value
*/
*/for (int num: numbers){
System.out.println(num);
}


/*
Expand Down
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