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F_Array.java
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F_Array.java
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public class F_Array {
public static void main(String[] args) {
/*
* To declare an array, you need to define the type of the elements with square
* brackets. For example, to declare an array of integers:
*/
int[] arr;
/**
* Now, you need to define the array's capacity, or the number of elements it
* will hold. To accomplish this, use the keyword new.
*/
arr = new int[5];
/**
* To reference elements in an array, type the name of the array followed by the
* index position within a pair of square brackets.
*/
arr[2] = 42;
String[] myNames = { "A", "B", "C", "D" };
/**
* Sometimes you might see the square brackets placed after the array name,
* which also works, but the preferred way is to place the brackets after the
* array's data type.
*/
System.out.println(myNames[2]);
int[] intArr = new int[5];
/**
* You can access the length of an array (the number of elements it stores) via
* its length property.
*/
System.out.println(intArr.length);
int[] myArr1 = { 6, 42, 3, 7 };
int sum = 0;
for (int z = 0; z < myArr1.length; z++) {
/**
* as the last element's index is myArr.length-1.
*/
sum += myArr1[z];
}
System.out.println(sum);
int[] primes = { 2, 3, 5, 7 };
/**
* The enhanced for loop (sometimes called a "for each" loop) is used to
* traverse elements in arrays.
*/
for (int t : primes) {
System.out.println(t);
}
/**
* The enhanced for loop declares a variable of a type compatible with the
* elements of the array being accessed. The variable will be available within
* the for block, and its value will be the same as the current array
* element.So, on each iteration of the loop, the variable t will be equal to
* the corresponding element in the array.
*/
/**
* =====================================MULTIDIMENTIONAL
* ARRAY====================================
*/
int[][] sample = { { 1, 2, 3 }, { 4, 5, 6 } };
int x = sample[1][0]; // The array's two indexes are called row index and column index.
System.out.println(x); // Outputs 4
int[][] myArr = { { 1, 2, 3 }, { 4 }, { 5, 6, 7 } };
myArr[0][2] = 42;
x = myArr[1][0]; // x=4
}
}