1. lab6 PROGRAMMING 1
metheds chapter5

2. BEFORE WE START Your Cell Phone Silent Please Keep Quite
Find Your Computer and Switch On
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3. content To define methods. To invoke methods with a return value.
To invoke methods without a return value.
To pass arguments by value.
To determine the scope of variables.
The Math Class.
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4. Defining a Method The syntax for defining a method is as follows:
modifier returnValueType methodName (list of parameters) {
// Method body; }
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5. Calling a Method
There are two ways to call a method in main, depending on whether the method returns a value or not.
1- If the method returns a value, a call to the method is usually treated as a value. For example,
example1 : int larger = max(3, 4);
System.out.println(larger);
calls max(3, 4) and assigns the result of the method to the variable larger.
2- Another example of a call that is treated as a value is
example2 : System.out.println(max(3, 4));
which prints the return value of the method call max(3, 4).
Example for first case
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6. method without a return value
void Method Example:
Open braces main
Call method
close braces main
Name of method
Parameter
Void not return
Body of method
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7. (cont..)
Output:
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8. method with a return value
Return value of type int
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9. Passing Parameters by Values
Parameter by value
call Method name
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10. scope of variables
A variable declared in a method is called a local variable.
The scope of a local variable starts from its declaration and continues to the end of the block that contains the variable.
A local variable must be declared and initialized before it isused.
Example :
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11. The Math Class
The Math class contains the methods needed to perform basic mathematical functions.
For example:
System.out.print(Math.pow(2,8));
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12. Exercise1 Write a class that contains the following two methods:
/** Converts from Celsius to Fahrenheit */
public static double celsiusToFahrenheit(double celsius)
/** Converts from Fahrenheit to Celsius */
public static double fahrenheitToCelsius(double fahrenheit)
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13. Cont…..
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14. Cont…..
output
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15. Exercise2 Write the following two methods:
// Return the reversal of an integer, i.e. reverse(456) returns 654
public static int reverse(int number)
// Return true if number is palindrome
public static boolean isPalindrome(int number)
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16. Exercise2
Ispalindrome method
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17. Exercise2
Revers method
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18. Cont…..
Output:
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19. Thank You !