resolved tasks - arrays

01/app.js

@@ -0,0 +1,4 @@
+const users = ['Janusz Kowalski', 'Robert Lewandowski', 'Jan Pawel', 'Edzia Gorniak', 'Marcin Najman'];
+
+console.log(users[0], users[2], users[4]);
+console.log(users.length);

02/app.js

@@ -20,4 +20,20 @@ function createRandomArray() {
 
 function getRandomInteger(min, max) {
     return Math.round(Math.random() * (max-min) + min);
-}
+}
+
+
+// function showArrayElement(arr){
+//     for (let i=0; i < arr.length; i++){
+//         console.log(arr[i]);
+//     }
+// }
+
+// showArrayElement(randomArray);
+
+function showArrayElement(arr){
+    arr.forEach((element) => console.log(element));
+    console.log(` Ostatni element tablicy to: ${arr[arr.length - 1]}`);
+}
+
+showArrayElement(randomArray);

03/app.js

@@ -1,2 +1,22 @@
 const n = 24;
-const oddNumbers = [];
+const oddNumbers = [];
+
+// for (let i = 0; i < n; i++){
+//     if(i%2 !== 0) {
+//         oddNumbers.push(i);
+//     }
+// }
+// console.log(oddNumbers);
+
+function showOddNumbers(maxValue){
+    let arr = [];
+
+    for (let i = 0; i < maxValue; i++){
+        if(i%2 !== 0) {
+            arr.push(i);
+        }
+    }
+    console.log(arr);
+}
+
+showOddNumbers(n);

04/app.js

@@ -1 +1,7 @@
-const years = [1980, 1934, 2002, 2019];
+const years = [1980, 1934, 2002, 2019];
+
+const currentDate = new Date();
+const currentYear = currentDate.getFullYear();
+
+const yearsToDate = years.map((element) => currentYear - element);
+console.log(yearsToDate);

05/app.js

@@ -1 +1,17 @@
-const numbers = [1, 2, 3, 4, 5, 6, 7];
+const numbers = [1, 2, 3, 4, 5, 6, 7];
+
+// const sum = numbers.reduce((acc, el) => {
+//     if(el%2===0){
+//         return acc+el;
+//     }
+//        return acc;
+//     }, 0);
+
+
+// console.log(sum);
+
+
+const evenNumbers = numbers.filter((element) => element%2===0);
+const sum = evenNumbers.reduce((acc, el) => acc + el, 0);
+console.log(sum);
+