Chapter 10: Input and Output

Input: Process of giving something to the computer. Standard Input: Input via keyboard.

Output: Process of getting something from the computer. Standard Output: Output displayed on monitor.

Header File: stdio.h (Standard Input Output) contains definitions for standard I/O functions like printf and scanf.

Definition: Used to display output on monitor. Can display text, constants, or variable values.

Syntax: printf("Control String", Argument List);

• Control String: Text, Format Specifiers (starts with %), Escape Sequences (starts with \).
• Argument List: Variables or values to be printed, matching the format specifiers.

Starts with % symbol. Determines data type, field width, and format.

• Integer: %d (decimal), %i (integer), %o (octal), %x (hex lower), %X (hex upper), %u (unsigned).
• Float: %f (float/double), %e (scientific lower), %E (scientific upper), %g (shortest of %f or %e).
• Character/String: %c (char), %s (string).

Field Width: Number of columns used to display value to text (e.g., %5d uses 5 columns).

Precision: Number of decimal places for floats (e.g., %.2f displays 2 decimal places).

Definition: Used to take input from the user. Stores input in specified variables.

Syntax: scanf("Format String", &variable1, &variable2, ...);

• Format String: Contains format specifiers matching the data types of variables.
• Address Operator (&): Must be used with variable names (except strings) to specify memory address.

Special characters starting with backslash (\) used to modify output format. Not printed themselves.

• \n: New Line. Moves cursor to start of next line.
• \t: Horizontal Tab. Moves cursor to next tab stop.
• \b: Backspace. Moves cursor one position back.
• \r: Carriage Return. Moves cursor to beginning of current line.
• \f: Form Feed (Page Break).
• \': Print Single Quote.
• \": Print Double Quote.
• \\: Print Backslash.

Functions from conio.h to input single characters.

• getch(): Get Character. Input not echoed (displayed) on screen. Often used to pause program output.
• getche(): Get Character Echo. Input is displayed on screen as typed.

• gets(): Get String. Reads a line of text (including spaces) until Enter is pressed. Replaces scanf limitation with spaces.
• puts(): Put String. Displays a string on screen and automatically adds a new line at the end.

• clrscr(): Clear Screen. Clears text from standard output. Defined in conio.h.
• sizeof(): Operator to find the size of data type or variable in bytes. (e.g., sizeof(int) returns 2).