Output

Objectives

We would like to :

Understand three output methods.

Notes

This is from Section 2.4.1 Basic Output and Formatted Output

We have already seen System.out.println()

```
System.out.println("Hello World"); 
```
This takes 0 or 1 argument
It will print this argument to the output and print a newline.
This allows us to view the value of variables.

System.out.println(pricePerGallon);
System.out.println(isFinished);
System.out.println(bigNumber);
System.out.println(anotherBigNumber);
System.out.println('\n');

System.out.print()

Nearly the same, but does not print a newline.
We can use this to put multiple outputs on the same line

totalPrice = gallons * pricePerGallon + gallons * TAX_PER_GALLON;
totalOz = numberOfCones * OZ_PER_CONE;

System.out.print("The total oz of ice cream needed is ");
System.out.print(totalOz);
System.out.println();

System.out.printf( format, value1, value2, ...)
- This is just a little more difficult, but well worth it.
- First provide a format string.
  - It can contain text.
  - It can also contain a format specifier.
    - This is something in the form %X
    - Where X will depend on the variable to be printed.
- Then a variable for each format specifier in the format string.

The %d specifier

%d is used for integers.
Oh and %n or \n will serve as a new line.
- SO the last example, that took two lines could be done with
- ```
System.out.printf("The total oz of ice cream needed is %d.%n", totalOz);
```
- We can specify multiple items
- ```
System.out.printf("We sold %d cones or %d oz.%n%n",numberOfCones, totalOz); 
```
- With %d there are a few other options
- %,d will print commas.
  - ```
  System.out.printf("A large number is %,d!%n", largeNumber);
```
- %nd will print an integer using at least n spaces.
  - If the space required is less than n, it will be printed right aligned.
  - ```
  System.out.printf("A large number is %30d!%n", largeNumber); 
```
- If the number has more digits than n, it will be ignored.
- ```
System.out.printf("A large number is %3d!%n", largeNumber); 
```
  - If n is negative, it will be printed left aligned.
  - ```
  System.out.printf("A large number is %-30d!%n", largeNumber); 
```

The %f specifier

%f is for float

%a.b5

a is the total width
b is the number of decimal points to print.
Either can be specified

The number will round up to the specified decimal points.

System.out.printf("The price per gallon is $%f.\n", pricePerGallon);
System.out.printf("The price per gallon is $%10f.\n", pricePerGallon);
System.out.printf("The price per gallon is $%.2f.\n\n", pricePerGallon);

System.out.printf("The tax per gallon is $%f.\n",TAX_PER_GALLON);
System.out.printf("The tax per gallon is $%.2f.\n",TAX_PER_GALLON);

There are more options, but these will do for now.
- See printf() at Oracle for more information.