Q1: which of the following identifiers represents an invalid variable name, and why?myNumber
my.Number
my-Number
my_Number
my Number
$myNumber
myNumber2
8myNumber
While
Q2: Write a JavaScript code to declare a variable called myNumber; initialize it with the number 7; add 3 to its value; and finally display the new value. (M150A final exam, Fall 2008)var myNumber;myNumber = 7;myNumber = myNumber + 3;document.write('The new value of myNumber is ' + myNumber);
Q3: Write a JavaScript code to do the following: Ask the user to enter his / her name Display on the screen: Welcome followed by the user namevar userName;
userName = window.prompt('Please enter your name','');
document.write('Welcome ' + userName);
Q4: Write a JavaScript code to compute and print the perimeter of a rectangle as follows: Ask the user to enter the length and width of the rectangle Compute the perimeter of the rectangle based on the formula:Perimeter = 2 (length + width) Print the computed perimeter in the output windowvar length, width, perimeter;length = window.prompt('Please enter the rectangle length','');length = parseFloat(length);width = window.prompt('Please enter the rectangle width','');width = parseFloat(width);perimeter = 2 * (length + width);document.write('The rectangle perimeter is ' + perimeter)
Q5: Write an equivalent JavaScript code to the following flow chart:
var grade;
grade = window.prompt('Please enter the grade','');grade = parseFloat(grade);
if (grade >= 90)
{document.write("Excellent");}else{document.write("Done");}
Q6: Write a JavaScript code to identify if a student passes specific course or failedBased on his final score according to the following: Read the final score from the user. If the final score is greater than or equal to 50, print on the screen Passed, otherwise print Failed.var score;
score = window.prompt('Please enter your score','');score = parseFloat(score);
if (score >= 50)
{document.write("Passed");}else{document.write("Failed");}
Q7: Write an equivalent JavaScript code to the following flow chart:
var grade;
grade = window.prompt('Please enter the grade','');grade = parseFloat(grade);
if (grade < 50)
{document.write('Failed' + '
' + 'Finished');}else{document.write('Passed' + '
' + 'Finished');}
Q8: Write a JavaScript code to identify if a student passes a specific course or failed based on his final score according to the following: Read the final score from the user Check the score, if it is less than 0 or greater than 100, print Invalid Score on the output screen, otherwise complete as follows: If the final score is greater than or equal to 50, print on the screen Passed, otherwise print Failedvar score;
score = window.prompt('Please enter your score','');score = parseFloat(score);
if (score < 0 || score > 100)
{document.write("Invalid Score");}else{if (score >= 50){document.write("Passed");}else{document.write("Failed");}}
Q9: Write a JavaScript code that will assign a grade to a student, based on his final score according to the following table:Score rangeGrade
90 - 100A
80 89B
70 79C
50 69D
0 49F
The program works as follows: Read the students final score. (Assume that the user will insert a score between 0 and 100) Assign the grade to the student according to the above table. Print the grade in the output window.var score, grade;score = window.prompt('Enter your score','');score = parseFloat(score);if (score >= 90){grade = 'A'}else{if (score >= 80){grade = 'B'}else{if (score >= 70){grade = 'C'}else{if (score >= 50){grade = 'D'}else{grade = 'F'}}}}document.write('The grade of ' + score + ' is ' + grade)
Q10: Write an equivalent JavaScript code to the following flow chart:
document.write('Hello' + '
');
var grade;
grade = window.prompt('Please enter the grade','');grade = parseFloat(grade);
if (grade < 0 || grade > 100)
{document.write('The grade is not correct');}else{if (grade
>= 50){document.write('Passed');}else{document.write('Sorry ' +
'Failed');}}document.write('
' + 'Thank you')
Q11: Trace the following JavaScript code giving the exact
output:var x, y;y = 7;x = 1 + 4 + 8;document.write('First, x = ' +
x + ' and y = ' + y);document.write('
');
x = y + 2;x = x + 6;x = 3 + x / 3;document.write("Now, x = " + x
+ 'and y = ' + y + "
");
x = y;y = 9;// y = y + 10;document.write("Finally, x = " + x + "and y = " + y);
Answer: First, x = 13 and y = 7Now, x = 8and y = 7Finally, x = 7and y = 9
Q12: Trace the following JavaScript code giving the exact output:var w, y, z, text1, text2, text3, text4;w = '12'; x = '5';y = 12; z = 5;text1 = "CAR"; text2 = "car";text3 = "cat"; text4 = "cairo";
if ((w < x) && (y > z))document.write("First" +
"
");elsedocument.write("Second" + "
");document.write("Guess" + "
");if ((text1 == text2) || (text3 <
text4))document.write("Third" + "
");elsedocument.write("Fourth" + "
");if ((z != 10) && (text2 < text3)){z = z *
10;document.write("Finally, it is a " + text2);document.write(" for
" + y + z);}else{z = z * 10;document.write("See
you");}document.write("
" + "The End - " + "text4");
Answer: FirstGuessFourthFinally, it is a car for 1250The End - text4
Q13: The following JavaScript code has some errors. Identify the errors and rewrite the code correctly.var my Value;if (myValue = 0window.write("OK");
var myValue;myValue = window.prompt('Please enter the value','');myValue = parseFloat(myValue);
if (myValue == 0){document.write("OK")};
Q14: The following JavaScript code has some errors and a missing statement. Identify the errors and rewrite the code correctly.var mark;bar bonus = 2;mark = window.pompt('Insert the student mark','');mark = mark + bonus;if mark >= 50document.write('Passed);Elsedocument.write('Failed');
var mark;var bonus = 0;mark = window.prompt('Insert the student mark','');mark = parseFloat(mark);mark = mark + bonus;if (mark >= 50){document.write('Passed');}else{document.write('Failed');}
Q15: Trace out the following JavaScript code and state how many different paths it has, showing a possible output of each path and discussing briefly the purpose of the two if-else statements included.var num1, num2, oper, result;
num1 = parseFloat(window.prompt('Enter the 1st number:',''));num2 = parseFloat(window.prompt('Enter the 2st number:',''));
oper = window.prompt('Enter the operator: (+ or -)','');if((oper == '+') || (oper == '-')){if (oper == '+'){result = num1 + num2;document.write(num1 + oper + num2 + '=' + result);}else{result = num1 - num2;document.write(num1 + oper + num2 + '=' + result);}}else{document.write('Invalid operator');}
Answer Q15: The given code has 3 different paths.1. For invalid operator rather than + or -, it will printout Invalid operator message.2. For + operator, it will printout the output of adding the two variables num1 and num2. For example if the user entered 5 and 7. The output message would be 5 + 7 = 12.3. For operator, it will printout the output so subtracting the variable num2 from num1. For example if the user entered 10 and 3, the output message would be 10 -3 = 7.
Q16: Trace the following code then answer the questions below:var x, y;x = 10;y = 0;while(x >= 6){x = x - 2;y = y + x;}
a. How many times will the loop be executed?3 times.b. What are the values of x and y after the execution of the above code?x = 4, y =18c. What do you expect to happen if the initial value of x was 5 instead of 10?If the initial value of x was 5 instead of 10, the condition (x >= 6) will evaluate false and the loop body will not evaluated at all. Hence, the values of x and y remain the same.Q17: Trace the following code then answer the questions below:var x, y;x = 1; y = 1;while (x != 7){y = y * x;x = x + 2;}
a. How many times will the loop be executed?3 times.b. What are the values of x and y after the execution of the above code?x = 7, y = 15c. What do you expect to happen if the initial value of x was 2 instead of 1?If the initial value of x was 2 instead of 1 it will be an infinite loop. This is because the value of x will be added by resulting 2, 4, 6, 8, 10, and thus the condition (x != 7) will never be false.
Q18: Given the following code: (M150A final exam, Fall 2009)for(var i = 0; i < 10; i++){document.write(i);}
a. What is the output?0123456789b. How would you modify the code so that it prints the numbers backwards?for (i = 9; i >= 0; i--){document.write(i);}
c. How would you modify the code so that it prints only the even numbers?for (i = 0; i < 10; i++){if (i % 2 == 0)document.write(i);}
or
for (i = 0; i < 10; i = i + 2){document.write(i);}
d. How would you modify the code so that it sums all the values of i and prints the final sum?var sum;sum = 0;for (i = 0; i < 10; i++){sum = sum + i;}document.write("final sum is " + sum);
Q19: Write a JavaScript program to print a table of consecutive even numbers from 2 to 30 and their square values.A sample output of this is as follows:24
416
636
28784
30900
for(var i = 2; i = 0; count = count - 1){document.write(string1.charAt(count));
}
Q26: Write a JavaScript code that takes a string from the user and outputs the number of vowels in that string. (M150A final exam, Fall 2009)[vowels are the letter a, e, i, o, u]var myString, counter = 0, ch;myString = window.prompt('Please enter a string','');for (i = 0; i < myString.length; i = i + 1){ch = myString.charAt(i);if (ch == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i' || ch == 'I' ||ch == 'o' || ch == 'O' || ch == 'u' || ch == 'U'){counter = counter + 1;}}document.write('The are ' + counter + ' vowels in the string');
Q27: What is the value of y after the execution of the following java script code?You are required to show how you have obtained the result. (M150A final exam, Fall 2009)var x = 4;var y = x + 2;var count = 1;while (count < x){y = y * 2;count = count + 1;}
Answer: 48
Q28: Write JavaScript code to calculate and print the area of a triangle as follows: Ask the user to enter the base and the height of the triangle. Calculate the area of the triangle based on the formula:area = 1 / 2 * (base * height) Print the calculated area in the output window.var base, height, area;base = window.prompt('Please enter the triangle base','');base = parseFloat(base);height = window.prompt('Please enter the triangle height','');height = parseFloat(height);area = 1 / 2 * (base * height);document.write('The triangle area is ' + area)
Q29: Using the while loop, write JavaScript code to do the following:a. Print the numbers from 1 to 20.var i = 1;while (i = 1){document.write(i);i = i - 1;}
c. Modify the code so that it prints only the even number from 1
to 20.var i = 2;while (i max){max = anArray[i];}}return
max;};function calcMin(anArray){var min = anArray[0];for( i = 1; i
< (anArray.length); i = i + 1){if(anArray[i] < min){min =
anArray[i];}}return min;};function calcPositive(anArray){var
positives = 0;for(i = 0; i < (anArray.length);i = i +
1){if(anArray[i] > 0){positives = positives + 1;}}return
positives;};function calcNegative(anArray){var negatives = 0;for(i
= 0; i < (anArray.length); i = i + 1){if(anArray[i] <
0){negatives = negatives + 1;}}return negatives;};function
calcZero(anArray){var zeroes = 0;for(i = 0; i <
(anArray.length); i = i + 1){if(anArray[i] == 0){zeroes = zeroes +
1;}}return zeroes;};function
displayInfo(anArray){document.write('myArray has the following
elements: ' + anArray + '
');document.write('The max value = ' + calcMax(anArray) + '
');document.write('The min value = ' + calcMin(anArray) + '
');document.write('The number of positive values = ' +
calcPositive(anArray) + '
');document.write('The number of negative values = ' +
calcNegative(anArray) + '
');document.write('The number of zero values = ' +
calcZero(anArray) + '
');};var myArray = [2, 0, 1, -4, 10, 3, -2, 0, 3,
5];displayInfo(myArray);
Q36:
var ourNumber, userNumber, count;ourNumber = 501;userNumber = window.prompt('Enter a number between 1 and 1000', '');userNumber = parseFloat(userNumber);count = 1;while ( ourNumber != userNumber){if (ourNumber < userNumber){window.alert('You are above the right number!');}else{window.alert('You are below the right number!');}userNumber = window.prompt('Try again :', '');userNumber = parseFloat(userNumber);count = count + 1;}document.write('You guessed the number after ' + count + ' tries!');