Chapter 4: Loops
What is the output, if n is 3? for (int i = 1; i <= n; ++i) { int factorial = 1; factorial = factorial * i; System.out.print(factorial + " "); } 1 1 1 1 2 3 1 2 6 Error: Cannot use the loop variable i inside the for loop
1 2 3
What is the ending value of sum, if the input is 2 5 7 3? All variables are ints. x = scnr.nextInt(); sum = 0; for (i = 0; i < x; ++i) { currValue = scnr.nextInt(); sum += currValue; } 5 10 12 15
12
What is the output, if the input is 3 2 4 5? All variables are ints. num = scnr.nextInt(); for (i = 0; i < num; ++i) { curr = scnr.nextInt(); System.out.print(curr); } 24 245 324 3245
245
What is the output? public static void main(String[] args) { for (int i = 0; i < 3; ++i) { System.out.print(i); } System.out.print(i); } 012 0122 0123 Error: The variable i is not declared in the right scope
Error: The variable i is not declared in the right scope
Which input for char c causes "Done" to be output next? c = 'y'; while (c = 'y') { // Do something System.out.println("Enter y to continue, n to quit: "); // Get c from input} System.out.println("Done"); 'y' only 'n' only Any value other than 'y' No such value (error comparing c and 'y')
No such value (error comparing c and 'y')
Which XXX causes every character in string inputWord to be output? for (XXX) { System.out.println(inputWord.charAt(i)); } i = 0; i < (inputWord.length() - 1); ++i i = 0; i < inputWord.length(); ++i i = 0; i < (inputWord.length() + 1); ++i i = 0; i <= inputWord.length(); ++i
i = 0; i < (inputWord.length()); ++i
For the given pseudocode, which XXX and YYY will output the sum of the input integers (stopping when -1 is input)? Choices are in the form XXX / YYY. val = Get next input XXX While val is not -1 YYY val = Get next input Put sum to output sum = val / sum = val sum = val / sum = sum + val sum = 0 / sum = sum + val sum = 0 / sum = val
sum = 0 / sum = sum + val
Which XXX and YYY will loop as long as the input is an integer less than 100? Choices are in the form XXX / YYY. w = scnr.nextInt(); while (XXX) { // Do something YYY; } w < 100 / w = scnr.nextInt() w >= 100 / (nothing) w < 100 / (nothing) w >= 100 / w = scnr.nextInt()
w < 100 / w = scnr.nextInt()
How many times does the while loop execute for the given input values of -1 4 0 9? userNum = 3; while (userNum > 0) { // Do something // Get userNum from input } 0 1 2 3
1
Which input value causes "Goodbye" to be output next? int x; x = scnr.nextInt(); while (x >= 0) { // Do something x = scnr.nextInt(); } System.out.println("Goodbye"); -1 0 1 No such value
-1
What is the output? int n; for (n = 0; n < 10; n = n + 3) { System.out.print(n + " ");} 0 1 2 3 4 5 6 7 8 9 1 4 7 10 0 3 6 9 0 3 6 9 12
0 3 6 9
What is the output? int columns; int rows; for (rows = 0; rows < 2; ++rows) { for (columns = 0; columns < 3; ++columns) { System.out.print("x"); } System.out.println(); } xxx xxx xx xx xx xx xx xx xxx xxx
xxx xxx
How many x's will be output? Assume row and col are ints. for (row = 0; row < 2; ++row) { System.out.print("x"); for (col = 0; col < 3; ++col) { // Do something } } 1 2 3 6
2
What is the output, if userVal is 5?int x; x = 100; if (userVal != 0) { int tmpVal; tmpVal = x / userVal; System.out.print(tmpVal); } 0 5 20 Error: The compiler generates an error
20
What is the output? int num = 10; while (num <= 15) { System.out.print(num + " "); if (num == 12) { break; } ++num; } System.out.print("Done"); 10 Done 10 11 Done 10 11 12 Done 10 11 12 13 14 15 Done
10 11 12 Done
How many times will the loop iterate, if the input is 105 107 99 103? x = scnr.nextInt(); while (x > 100) { // Do somethingx = scnr.nextInt(); } 1 2 3 4
2
For the given pseudocode, which XXX and YYY will output the number of times that 10 is input (stopping when 0 is input)? Choices are in the form XXX / YYY. count = 0 val = Get next input While val is not 0 If val == 10 XXX Else YYY val = Get next input Put count to output count = count + 1 / count = 0 count = count + 1 / (nothing) count = count + val / (nothing) count = count + val / count = 0
count = count + 1 / (nothing)
Which YYY outputs the string in reverse? Ex: If the input is "Oh my", the output is "ym hO". int i; String str; str = scnr.nextLine(); for (YYY) { System.out.print(str.charAt(i)); } i = str.length(); i < 0; --i i = str.length(); i > 0; --i i = str.length() - 1; i >= 0; --i i = str.length() + 1; i > 0; --i
i = str.length() - 1; i >= 0; --i
A loop should sum all inputs, stopping when the input is 0. If the input is 2 4 6 0, sum should end with 12. What should XXX, YYY, and ZZZ be? Choices are in the form XXX / YYY / ZZZ. int sum; int currVal; XXX; currVal = scnr.nextInt(); while (YYY) { ZZZ; currVal = scnr.nextInt(); } sum = 0 / currVal != 0 / sum = sum + currVal sum = currVal / currVal == 0 / sum = currVal sum = 1 / currVal != 0 / sum = sum + 1 sum = scnr.nextInt() / currVal == 0 / sum = scnr.nextInt()
sum = 0 / currVal != 0 / sum = sum + currVal
For the given pseudocode, which XXX and YYY will output the smallest non-negative input (stopping when a negative value is input)? Choices are in the form XXX / YYY. min = 0 val = Get next input min = val While val is not negative If XXX YYY val = Get next input Put min to output val > 0 / min = val min < val / val = min val > min / val = min val < min / min = val
val < min / min = val
Which input value causes the loop body to execute a 2nd time, thus outputting "In loop" again? String s = "Go"; while ((!s.equals("q")) && (!s.equals("Q"))) { System.out.println("In loop"); s = scnr.next(); } "q" only "Q" only Either "q" or "Q" "Quit"
"Quit"
What is the output? int x = 18; while (x > 0) { // Output x and a space x = x / 3; } 6 2 6 2 0 18 6 2 18 6 2 0
18 6 2
What is the output if count is 4? for (i = count; i > 0; --i) { // Output i } 4 321 4321 43210
4321
How many x's will be output? i = 1; while (i <= 3) { j = 1; while (j <= i) { System.out.print("x"); ++j; } System.out.println(); ++i; } 0 3 4 6
6
What is the output, if the input is 3 2 1 0? x = scnr.nextInt(); while (x > 0) {System.out.print(2 * x + " "); } 6 6 4 2 6 4 2 0 6 6 6 6 6 ... (infinite loop)
6 6 6 6 6 ... (infinite loop)
Which for loop will iterate 100 times? for (i = 0; i < 99; i++) for (i = 1; i < 99; i++) for (i = 0; i < 100; i++) for (i = 1; i < 100; i++)
for (i = 0; i < 100; i++)
The program should output even values between -10 and 10 (inclusive), so -10 -8 ... 8 10. What should XXX be? for (XXX) { System.out.print(i + " "); } i = -10; i < 10; i = i + 2 i = -10; i <= 10; i = i + 2 i = -10; (i * 2) < 10; ++i i = -10; (i * 2) <= 10, ++i
i = -10; i <= 10; i = i + 2
The program should determine the largest integer seen. What should XXX be if the input values are any integers (negative and non-negative)? All variables are ints and have unknown initial values. for (i = 0; i < 10; ++i) { currValue = scnr.nextInt(); if (i == 0) { // First iteration XXX; } else if (currValue > maxSoFar) { maxSoFar = currValue; } } maxSoFar = 0 maxSoFar = currValue currValue = 0 currValue = maxSoFar
maxSoFar = currValue
What is the output? char letter1; char letter2; letter1 = 'p'; while (letter1 <= 'q') { letter2 = 'x'; while (letter2 <= 'y') { System.out.print("" + letter1 + letter2 + " "); ++letter2; } ++letter1; } px px py qx qy px py qx qy
px py qx qy
