Accessing Arrays
Given the following 2d array:
double [][] ma = {{7.73, 8.89}, {9.15, 4.8, 9.70, 3.922}, {8.63, 7.76, 1.2}, {3.2, 1.77, 11.53}};
What is the length of ma[2]?
3
Write a loop to traverse through a 2d array named arr. Assume the array could be jagged.
for(int i = 0; i < arr.length; i++) {
for(int j = 0; j < arr[i].length; j++) {...}
}
Write the code to create the following array. Give your array the name ma.
[[0, 0, 0],
[0, 0, 0]]
int[][] ma = new int[2][3];
Determine the output:
int[][] a={{3,2,1},{6,5,4},{9,8,7}};
for (int y = 1; y>=0; y--) {
for (int x = 2; x>=0; x--) {
System.out.print(a[y][x]+",");
}
}
4, 5, 6, 7, 8, 9
In database management, what does the acronym "SQL" stand for?
Structured Query Language
Given the following 2d array:
String [][] strs= {{"hi"}, {"how", "are", "you"}, {"I", "okay"}, {"bye"}};
What is the length of strs[1][3]?
Does the following loop print the array z by row first order or column first order?
for(int y=0; y<z.length; y++){
for(int x=0; x<z[y].length; x++) {
System.out.print(z[y][x]+",");
}
System.out.println();
}
row first
Write the code to initialize the following jagged array:
[[1, 2, 3],
[4],
[5, 6]]
int[][] arr = {{1, 2, 3}, {4} {5, 6}};
int[][] z = {{4, 7, 2}, {1, 3, 5}, {9, 0, 2}};
for(int y=0; y<z.length; y++){
for(int x=0; x<z[y].length; x++) {
System.out.print(z[x][y]+",");
}
System.out.println();
}
4, 1, 9,
7, 3, 0,
2, 5, 2,
(This is what it means by column first order btw)
What does the acronym "HTML" stand for in web development?
HyperText Markup Language
What is the element at arr3[0][1][2]?
int[][][] arr3 = {{{6, 14}, {2, 7, 3}, {8}}, {{1, 3, 5}, {7, 3, 5, 2}}};
3
Does the following code print the elements of array a in ascending or descending order?
int[][] a={{3,2,1},{6,5,4},{9,8,7}};
for (int y = 2; y>=0; y--){
for (int x = 0; x<3; x++){
System.out.print(a[y][x]+",")
}
}
descending order
Write the method getCol which gets a copy of a column from a 2d arr given col. Assume arr is a rectangular array and col is in bounds.
public static int[] getCol(int[][] arr, int col) {
...
}
int[] colcopy = new int[arr.length];
for(int i = 0; i < colcopy.length; i++)
colcopy[i] = arr[i][col];
return colcopy;
What does the following function do? (Don't determine the output, but explain in words)
int max = 0;
for(String[] sArr : abc) {
int sum = 0;
for(String s : sArr) sum += s.length;
if(sum > max) max = sum;
}
return max;
Finds the row with the most characters.
Which data structure follows the Last In, First Out (LIFO) principle?
Stack
Examine the code below and fill in the numbers required to make arr the same as x:
int[][] x = new int[2][3];
for(int i = 0; i < x.length; i++) {
for(int j = 0; j < x[i].length; j++) {
x[i][j] = i + j;
}
}
int[][] g = {{_, _, _}, {_, _, _}};
int[][] g = {{0, 1, 2}, {1, 2, 3}};
for(int i = 0; i < 5; i++) {
for(int j = 7; j >= 0 ; j--) {
if(j > i) sysout("x");
}
}
25
Fill 2d array with ascending numbers starting from 1.
public static void numberEveryCell(int[][] ma) {
}
int temp = 1;
for (int i = 0; i < ma.length; i++) {
for(int j = 0; j < ma[i].length; j++) {
ma[i][j] = temp++;
}
}
String[][] twoD = {{"AV", "J"}, {"JA", "VA", "A"}, {"JA", "J"}, {"AV", "V", "A"}};
Determine the output:
for(String[] sArr : twoD){
for(int i = 0; i < sArr.length; i++) {
if(i % 2 == 0) sysout(sArr[i]);
}
}
AV
JA
A
JA
AV
A
What is the term for a programming error that causes a program to behave unexpectedly, often resulting in crashes or unintended behavior?
Bug
Given the following matrix, which code segment will result in "mao"?
String[][] matrix = {{"r","m","c","h","q","m"},
{"b","j","d","e","z","w"},
{"v","w","t"},
{"f","r","k","n","a","o"}};
matrix[0][1] + matrix[3][4] + matrix[3][5]
Assume there exists an int[][] z that is a square shape. Write the code to print the diagonal of z. (Either diagonal works)
for(int i = 0; i < z.length; i++) {
for(int j = 0; j < z[i].length; j++) {
if(i = j) System.out.println(z[i][j] + " ");
}
}
Explain the difference between a shallow copy and deep copy for arrays.
In a deep copy, each element of the array is copied to a newly created array. This array has a different memory address than the original array. Any changes made to the new array will not affect the original array.
Determine the Output:
int[] nums1 = { 14, -23, 90 };
increment(nums1);
System.out.println(Arrays.toString(nums1);
_____________________________________
public static void increment(int[] arr) {
for(int i = 0; i < arr.length; i++) arr[i]++;
}
[15, -22, 91]
This programming language, developed by James Gosling at Sun Microsystems, is often used for building mobile and web applications.
Java