- (fill in the blank) the length of the array is fixed. If you need to expand, you must create a new array. The length of the original array should be copied to the new array.
- (fill in the blank) in java, when an array type variable passes a value, it actually passes the address of the array.
- (short answer) there are several ways to expand an array. What are the different ways?
Create a new array and move the contents of the original array to the new array.
- Use a loop to change the original array address to a new large array address
- Use a function to achieve the same expansion effect
- The system defined function system.arraycopy is used to realize the capacity expansion;
- The system defines the function copyof to realize the capacity expansion;
- (fill in the blank) the two-dimensional array implemented in Java is actually the nesting of one-dimensional array.
2-D array also supports display initialization
Two dimensional array can not specify low dimension, and high dimension must be specified; \
- (programming) complete the bubble sorting algorithm of the array. Given the array: int[] a = {1,2,3,4,5}, use the bubble sorting to sort it in the order of large to small, and then output the result.
Bubble sorting: compared with two adjacent numbers, cyclic bubble n-1 Second;
class paixu{
//Bubble sort
public static void main(String[] args) {
int[] a = {4,5,2,1,6,83,9,7,0};
for(int i=1;i<a.length;i++){//Note: the initial value of i here should start from 1;
//Inner loop control sorting times
for (int j=0;j<(a.length-i);j++) {
//Exchange order, compare the size of two numbers, large backward
if (a[j]>a[j+1]) {
int t;
t=a[j];
a[j]=a[j+1];
a[j+1]=t;
}
}
}
//Loop again to see if the sorting is successful
for (int i=0;i<a.length;i++) {
System.out.print(a[i]+"\t");
}
}
}- (programming) complete the selection sorting algorithm of the array in the above question.
Select sort: ratio of one number to all remaining numbers
class xuanze{
//Select sort to compare a number to all remaining numbers
public static void main(String[] args) {
int[] a = {4,5,2,1,6,83,9,7,0};
//Outer loop starts from 0, loop length-1 times
for (int i=0;i<a.length-1 ;i++ ) {
//From i+1 to length,
for (int j=i+1;j<a.length ;j++ ) {
//Compare the first number with all the following numbers in turn. Put the smallest number first and change the order
if (a[i]>a[j]) {
int t=a[i];
a[i]=a[j];
a[j]=t;
}
}
}
//Loop through the elements of the array again
for (int i=0;i<a.length ;i++ ) {
System.out.print(a[i]+"\t");
}
}
}- (programming) complete the fast sorting algorithm of the array in the 4 questions.
class kuaisu{
//Quick sort
public static void main(String[] args) {
int[] a = {4,5,2,1,6,83,9,7,0};
//Sort uses the quick sort method,
java.util.Arrays.sort(a);
//Loop through the elements of the array again
for (int i=0;i<a.length ;i++ ) {
System.out.print(a[i]+"\t");
}
}
}
Improve exercises:
1. (encoding) output a given array int[] a={1,2,3,4,5,6} in reverse order.
class nixu{
//Output a given array int[] a={1,2,3,4,5,6} in reverse order.
public static void main(String[] args) {
int[] a = {1,2,3,4,5,6};
for (int i=a.length-1;i>=0 ;i-- ) {
System.out.print(a[i]+"\t");
}
}
}