JavaScript/Loops/Exercises

Topic: Loops __TOC__ for (Part 1) {What is the result? "use strict"; for (const i = 3; i <= 6; i++) { alert(i); } // |type="()"} - Numbers from 3 to 5 - Numbers from 3 to 6 + Runtime error - None of the above {What is the result? "use strict"; for (let i = 10; i >= 0; i--) { alert(i); i--; } // |type="()"} - Numbers from 10 to 0 + Even Numbers from 10 to 0 - Odd Numbers from 10 to 0 - Runtime error - None of the above {What is the result? "use strict"; for (let i = 5; i < 10; ) { alert(i); i = i + 3; alert(i); } // |type="()"} - 5, 8 - 5, 8, 8 - 5, 8, 11 + 5, 8, 8, 11 - Runtime error - None of the above {What is the result? "use strict"; const myString = "abc"; for (let i = myString.length - 1; i >= 0; i--) { alert(myString[i]); } // |type="()"} - a, b, c + c, b, a - Runtime error - None of the above for (Part 2) 1. Write a script that uses two nested loops and shows the following strings: 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100% "use strict"; // by convention, fundamental constants like PI or such constants that // determine the behavior of your program are written in uppercase const START = 1; const END = 10; let myString = ""; for (let o = START; o <= END; o++) { myString = ""; for (let i = 1; i <= o; i++) { myString += i + ", "; } alert(myString); } 2. Write a script that uses two nested loops and shows the following strings, including the apostrophes: Next line is: "1, 3, 5, 7, 9," Next line is: "1, 3, 5, 7," Next line is: "1, 3, 5," Next line is: "1, 3," Next line is: "1," (Bonus challenge: Remove the last comma) 100% "use strict"; // by convention, fundamental constants like PI or such constants that // determine the behavior of your program are written in uppercase const START = 1; const END = 10; let myString = ""; for (let o = END; o >= START; o = o - 2) { myString = 'Next line is: "'; for (let i = 1; i <= o; i = i + 2) { myString += i + ", "; } myString += '"'; alert(myString); } 3. Write a script that creates a 'quadrat' with edge length 4. It consists of 'x's at one diagonal and dots at the other places. Hint: Create an empty string and - within the loop - append characters to the string. The line break is "\n". Lastly, show the string. Use for loops. In a second step, change only one single statement to create an according 6 x 6 quadrat. x... .x.. ..x. ...x 100% "use strict"; // by convention, fundamental constants like PI or such constants that // determine the behavior of your program are written in uppercase const LENGTH = 4; let result = ""; for (let i = 0; i < LENGTH; i++) { for (let j = 0; j < LENGTH; j++) { if (i === j) { result = result + "x"; } else { result = result + "."; } } result = result + "\n"; } alert(result); // to create a 6x6 quadrat, just change the variable LENGTH to '6' 4. Write a script that creates an 'arrow' with two heads: "<======>". The length of the arrow is determined by a variable. Changing this variable will result in an arrow of a different size. <=====> or <===================> 100% "use strict"; // by convention, fundamental constants like PI or such constants that // determine the behavior of your program are written in uppercase const LENGTH = 4; // left head let result = "<"; for (let i = 0; i < LENGTH; i++) { result = result + "="; } // right head result = result + ">"; alert(result); for..in, for..of, entries() 1. Write a script that creates an Object with some of your personal characteristics shows all properties (key and value) within a for..in loop shows all properties (key and value) by using the Object.entries() method. 100% "use strict"; // an example const myObj = {firstName: "Marilyn", familyName: "Monroe", born: 1953}; for (const key in myObj) { // 'in' delivers the keys alert('First: ' + key + ' / ' + myObj[key]); } // 'entries()' delivers key and value within an array-element for (const [key, val] of Object.entries(myObj)) { alert('Second: ' + key + ' / ' + val); } 2. Write a script that creates an Array with all odd numbers smaller than 10 creates a string with all those numbers plus a delimiter using a for..of loop shows the string after the loop 100% "use strict"; const myArray = []; for (let x = 1; x < 10; x = x + 2) { myArray.push(x); } let result = ""; for (const value of myArray) { result += value + '; '; } alert(result); {What is the result? "use strict"; const myArray = [10, 11, 12]; for (const x in myArray) { alert(x); } // for (const x of myArray) { alert(x); } // |type="()"} + 0, 1, 2 followed by 10, 11, 12 - 10, 11, 12 followed by 0, 1, 2 - Runtime error {What is the result? "use strict"; const myArray = [10, 11, 12]; for (const x in myArray) { alert(myArray[x]); } // |type="()"} - 0, 1, 2 + 10, 11, 12 - Runtime error forEach 1. Write a script that defines an array const arrIntegers = [3, 8, -3, 0]; use a .forEach construction to fill a second array with the quadratic values (9, 64, ...) of the first array show the second array 100% "use strict"; // declare both arrays const arrIntegers = [3, 8, -3, 0]; const arrQuadrat = []; // empty // compute the quadrats arrIntegers.forEach((elem) => arrQuadrat.push(elem * elem)); // show the result arrQuadrat.forEach(elem => alert(elem));