Page 372 - Computer_Science_F5

class MyClass { In the piece of code provided, both the
// lines show instance variable instance variable and the parameter are
named “length.” This creates ambiguity
int length; for the Java compiler. To resolve such Chapter Five: Object oriented programming with Java

// lines show parameter ambiguity, you can use the “this”
FOR ONLINE READING ONLY
keyword. When you write and run the
MyClass(int length){
above codes without this keyword you
length = length; may get ambiguous output such as zero

} or other. Program Example 5.27 shows
the use of this keyword, the output is
} shown in Figure 5.29.

Programe Exampe 5.27:

Java code using this keyword for ambiguous variable names

class MyClass {
// lines show instance variable

int length;
// lines show parameter
MyClass(int length){
this.length = length;

}
public static void main(String[] args) {
MyClass obj = new MyClass(23);
System.out.println(“obj.length = “ + obj.length);
}

}

Output:

Figure 5.29: Output of ambiguous variable

(ii) Used in getters and setters methods

In these methods, this keyword is used to assign value inside the setter method and
also to access value inside the getter method as shown in Program Example 5.28.

363
Student’s Book Form Five

Computer Science Form 5.indd 363 23/07/2024 12:34