Array Index and length
In this chapter you will learn:
Array Index
Array stores elements and we use index to reference a single value in an array. The starting value of the index is 0. If you try to reference elements with negative numbers or numbers greater than the array length, you will get a run-time error.
public class Main {
public static void main(String args[]) {
/*from j av a 2 s . co m*/
int days[] = {31, 28, 31,};
System.out.println("days[2] is " + days[10]);
}
}
It generates the following error.
We usually use a for loop to access each element in an array. The following code uses a one-dimensional array to find the average of a set of numbers.
public class Main {
public static void main(String args[]) {
double nums[] = {10.1, 11.2, 12.3, 13.4, 14.5};
double result = 0;
int i;/* j av a 2s . c o m*/
for (i = 0; i < 5; i++)
result = result + nums[i];
System.out.println("Average is " + result / 5);
}
}
The output:
Arrays length
Array size, arrayName.length, holds its length.
The following code outputs the length of each
array by using its length property.
public class Main {
public static void main(String args[]) {
int a1[] = new int[10];
int a2[] = {1, 2, 3, 4, 5};
int a3[] = {4, 3, 2, 1};
System.out.println("length of a1 is " + a1.length);
System.out.println("length of a2 is " + a2.length);
System.out.println("length of a3 is " + a3.length);
}//from j a v a 2 s.co m
}
This program displays the following output:
Next chapter...
What you will learn in the next chapter:
- How is the multidimensional arrays stored
- How to create a three-dimensional array
- What are Jagged array
- How to initialize multidimensional arrays during declaration
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