1 / 32

Today’s topic:

Today’s topic:. Arithmetic expressions. Arithmetic expressions. binary (two arguments) arithmetic operators +, -, *, /, % (mod or modulus) unary (one arg ) operators -, + Order of operations just like you’d expect: Please Excuse My Dear Aunt Sadie. Can use () to override.

rasul
Download Presentation

Today’s topic:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Today’s topic: • Arithmetic expressions

  2. Arithmetic expressions • binary (two arguments) arithmetic operators • +, -, *, /, % (mod or modulus) • unary (one arg) operators • -, + • Order of operations just like you’d expect: • Please Excuse My Dear Aunt Sadie. • Can use () to override.

  3. Arithmetic expressions • How would we code the following? • Let n be 2 and k be 2n+1.

  4. Arithmetic expressions • How would we code the following? • Let n be 2 and k be 2n+1. int n = 2; int k = 2*n+1; Or int n, k; n = 2; k = 2 * n + 1;

  5. Arithmetic expressions • How would we code the following? • Let n be 2 and k be 2n+1. int n = 2; int k = 2*n+1; Note: The rhs of the equals is always evaluated first and is assigned to the lhs. Therefore, you cannot say: int 2 = n; Or 2*n+1 = k;

  6. Arithmetic expressions • Example from physics: F = M A (force = mass x acceleration). • How would we code this in Java?

  7. Arithmetic expressions • Example from physics: • F = M A (force = mass x acceleration). • How would we code this in Java? double mass = 12.0; double acc = 13.9; double force = mass * acceleration; System.out.println( "force = " + force );

  8. Differences between int and double • int (integer) and double (real numbers) are different. • int is a subset of double but ints are much faster to calculate than doubles • So use ints whenever you can but be aware of the following: int n = 5 / 2; int k = 9 / 10;

  9. Differences between int and double • 5 is an int. • 5.1 is a double. • 5.0 is a double. • 5.7f is a float • Range of values: • int -2 billion to +2 billion • double 4.9x10-324 to 1.8x10308 • float 1.4x10-45 to 3.4x1038

  10. Converting doubles to ints • When we convert, we will typically lose something. • Consider converting 12.9 to an int. There is no int 12.9. • So the compiler will issue a message. To inform the compiler that we really wish to do this, we can use a cast. int i; double d = 12.9; i = (int) d; //What do you think is in i now?

  11. Converting doubles to ints inti; double d = 12.9; i = (int) d; //What do you think is in i now? //how can we round instead?

  12. Let’s check what we’ve learned so far (using jGrasp). class FirstExample { public static void main ( String[] params ) { //arithmetic //output } }

  13. ints and mod (%) • What is the result of the following: int k = 5 / 2; What is the remainder? % is used to calculate the remainder. int remainder = 5 % 2;

  14. Float vs. double • Recall range of values: • double 4.9x10-324 to 1.8x10+308 • float 1.4x10-45 to 3.4x10+38 • Recall that we used a cast to convert a double to an int: • double d = 12.9; • inti = (int) d; • This is because a double won’t fit into an int. Will a double fit into a float?

  15. Increment and decrement operators (++ and --) • What does the following do: • inti = 12; • i = i + 2;

  16. Increment and decrement operators (++ and --) • We often see code like the following: int value = 12; … value = value + 1; … value = value + 1; … value = value + 1;

  17. Increment and decrement operators (++ and --) • We often see code like the following: int value = 12; … value = value + 1; … value = value + 1; … value = value + 1; int value = 12; … value++; //post increment … ++value; //pre increment … value++;

  18. Increment and decrement operators (++ and --) • We often see code like the following: int value = 12; … value = value - 1; … value = value - 1; … value = value - 1; int value = 12; … value--; //post decrement … --value; //pre decrement … value--;

  19. Increment and decrement operators (++ and --) • We can use these operators in expressions as well (but don’t get carried away): int where = 92; int k = 7; where = k++; int j = --where;

  20. Convert the following to Java expressions:

  21. Write a program that . . . class MyProgramTemplate { public static void main ( String param[] ) { System.out.println( "hi there" ); } //end main } //end class

  22. Write a program that . . . Declares a variable for the radius of a circle with a value of 12.7. Calculates the circumference. Calculates the area. Prints out the radius, circumference, and area. class MyProgramTemplate { public static void main ( String param[] ) { System.out.println( "hi there" ); } //end main } //end class

  23. Write a program that . . . Declares a variable for the radius of a circle with a value of 12.7. Calculates the circumference. Calculates the area. Prints out the radius, circumference, and area. class MyProgramTemplate { public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. //Calculate the circumference. //Calculate the area. //Print out the radius, circumference, and area. } //end main } //end class

  24. Write a program that . . . What types of things are radius, circumference, and area? class MyProgramTemplate { public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. //Calculate the circumference. //Calculate the area. //Print out the radius, circumference, and area. } //end main } //end class

  25. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. //Calculate the area. //Print out the radius, circumference, and area. } //end main

  26. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = ?; //Calculate the area. //Print out the radius, circumference, and area. } //end main

  27. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * 3.14 * radius; //Calculate the area. //Print out the radius, circumference, and area. } //end main

  28. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * Math.PI * radius; //Calculate the area. //Print out the radius, circumference, and area. } //end main

  29. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * Math.PI * radius; //Calculate the area. double area = Math.PI * radius * radius; //Print out the radius, circumference, and area. } //end main

  30. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * Math.PI * radius; //Calculate the area. double area = Math.PI * radius * radius; //Print out the radius, circumference, and area. System.out.println( " radius = " + radius ); ? } //end main

  31. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * Math.PI * radius; //Calculate the area. double area = Math.PI * radius * radius; //Print out the radius, circumference, and area. System.out.println( " radius = " + radius ); System.out.println( " circumference = " + circ ); System.out.println( " area = " + area ); System.out.println( " Bye."); } //end main

  32. Write a program that . . . public static void main ( String param[] ) { System.out.println( "hi there" ); //Declare a variable for the radius of a circle with a value of 12.7. double radius = 12.7; //Calculate the circumference. double circ = 2 * Math.PI * radius; //Calculate the area. double area = Math.PI * radius * radius; //Print out the radius, circumference, and area. System.out.print( " radius = " + radius + ", " ); System.out.print( " circumference = " + circ + ", " ); System.out.println( " area = " + area + "." ); System.out.println( " Bye."); } //end main

More Related