Basic IO

Key Information

Basic information about SHARP's display, there's only space available for 26 characters, If the length of the information displayed exceeds that number the items at the end of the print list will not be seen.

`PRINT`

It is the main statement to produce output, it has several different variations.

The general format of the PRINT statement is the word PRINT followed by an item or a list of items to be printed. These include character strings, expressions, or names of variables whose values will be printed.

Statement Overview

";": Inserts a natural cadence, which results in one space between arguments.
",": Creates a tab jump, equivalent to 8 spaces, between arguments. Strings are left-aligned or "left justified", while numbers are right-aligned or "right justified".
Argument Calculations: The PRINT statement can perform calculations on arguments and display the result.
Comma Limit: Using a comma , in the PRINT statement restricts the number of arguments to a maximum of two.

    10 BS = " BE "
    20 T = 2
    30 PRINT T; BS; " OR NOT"; 12/3 - 2; BS

`PAUSE`

It is a semi-automatic form of the PRINT statement, with the difference that the output remains on the display for a fixed and brief period of time. Basically a PRINT statement followed by a countdown. When the countdown completes, the program automatically continues to the next statement.

All of the various techniques for the PRINT statement are also applicable here. These 2 statements can be mixed at will. It seems like it can only be used in "Programmer mode".

     10 PAUSE "DO";
     20 PAUSE "RE";
     30 PAUSE "MI";
     40 PAUSE "FA";
     50 PAUSE "SOL";
     60 PAUSE "LA";
     70 PAUSE "SI";
     80 PAUSE "DO"

`INPUT`

The INPUT statement in BASIC is used to gather user-provided data during program execution. It allows programmers to prompt users for specific information and store their responses in variables.

Different Usages:

Basic Syntax: The simplest form of the INPUT statement is
```
INPUT variable-name
```
When executed, it displays a ? on the screen, signaling the user to enter data.
Prompting the User: To make the prompt more informative, the INPUT statement can include a custom message using a character string
```
INPUT "prompt message"; variable-name
```
This form displays the specified prompt followed by a blinking cursor on the same line, where the user can enter their input.
Advanced Prompting: A variation of the prompt uses a comma instead of a semicolon:
```
INPUT "prompt message", variable-name
```
This version clears the prompt message once the user starts typing their response, replacing it with the input.

Key Notes

The expected type of data (numeric or character) must match the variable type.
The INPUT statement can gather multiple data items at once by specifying a list of variables separated by commas:
```
INPUT var1, var2, var3
```

`WAIT`

The WAIT statement in BASIC allows the programmer to control how long information displayed by the PRINT statement stays on the screen. It modifies the operation of the PRINT statement, allowing the displayed information to remain visible for a specified period of time.

The argument is optional. If no argument is provided, the default behavior is "infinite", meaning the information will remain on the screen until the user presses the Enter key. This is the default mode in many programs.
If an argument is provided, all subsequent PRINT statements will hold their information on the screen for a time period proportional to the specified argument. This is similar to the PAUSE statement, but unlike PAUSE, the WAIT statement's time period is variable.

Argument Values

The argument value must be between 0 and 65535.
- WAIT 0 causes the information to be displayed so quickly that it is unreadable.
- WAIT 65535 causes the information to stay on the screen for about 17 minutes.
- WAIT 64 results in a display time of about 1 second.
- WAIT 3840 gives a display time of about 1 minute.

To reset the PRINT statement back to its default behavior (waiting for the user to press Enter), simply use WAIT with no argument.

      WAIT argument (64)

Key Notes:

The WAIT statement has no effect on the PAUSE statement.
The time specified by the WAIT statement can be adjusted for more precise control over the display duration.

`READ`

The READ statement in BASIC serves as a mechanism to retrieve data from DATA statements and assign it to specified variables. Each variable in the READ statement is assigned the next available data item from the list.

The READ statement consists of the keyword READ, followed by a comma-separated list of variable names. These variables can be either numeric or character types.

Key Notes:

Execution Requirements: For every execution of a READ statement, there must be a corresponding data item within a DATA statement. If no data item is available for a variable, the program halts and signals an error.
Type Matching: The data type (numeric or character) of the retrieved item must match the type of the variable to which it is being assigned. A mismatch in type results in an error.

     120 READ NS, WT , CS, SX$, L

`DATA`

The DATA statement allows the programmer to embed data directly within the program. This data can include numbers (in real or scientific notation) and character strings, which are separated by commas.

DATA statements may appear anywhere within a program; however, grouping them at the beginning of the program is a widely adopted convention among programmers.

Extra data items not used during the program execution are ignored.

     10 DATA "MOBY DICK", 20000, " WHITE". " M'', 112

`RESTORE`

The RESTORE statement in BASIC is used to reset the data pointer, allowing the program to re-read data items from DATA statements.

The RESTORE statement enables the re-use of some or all values defined in DATA statements. It resets the data pointer to a specified location, allowing subsequent READ statements to retrieve previously used data items.

Different Usages:

Default Behavior: When executed without additional parameters, the RESTORE statement resets the pointer to the first DATA statement in the program. SubsequentREAD statements will then begin reading from the start of the data list.
Selective Restoration: The RESTORE statement can specify a starting point using either a line number or a label.

     RESTORE line_number (150)

This causes the program to begin re-reading data items from the DATA statement located at the specified line number.

Alternatively, a label can be assigned to a DATA statement, and the RESTORE statement can use this label to target the starting point:

     RESTORE label ("X")