Input, Output & Assignment

An assignment statement stores a value into a variable. In CIE pseudocode the assignment operator is the left-pointing arrow <-, which you can read aloud as "becomes" or "gets".

Syntax

<Variable> <- <Value or Expression>

Examples

Score <- 100
Price <- 9.99
Name <- "Alice"
Total <- Price * Quantity
Counter <- Counter + 1

The right-hand side is evaluated first, and the result is then stored in the variable on the left. This is why Counter <- Counter + 1 works — it means "take the current value of Counter, add 1, and store it back into Counter".

The INPUT statement reads a value from the keyboard (or another input device) and stores it in a variable. The program pauses until the user types something and presses Enter.

Syntax

INPUT <Variable>

Examples

DECLARE Name : STRING
DECLARE Age : INTEGER

INPUT Name
INPUT Age

Notice that the variable must be declared first, before you can read a value into it. The variable's data type decides what kind of input the program expects.

OUTPUT "Please enter your name: "
INPUT Name

The OUTPUT statement displays information on the screen. You can print text (in double quotes), the value of variables, or a mixture of both — joined together with the + operator.

Syntax

OUTPUT <Item1> [+ <Item2> + ...]

Examples

OUTPUT "Hello, world!"
OUTPUT Name
OUTPUT "Your score is " + Score
OUTPUT "Total: " + Price * Quantity

Text inside double quotes (a string literal) is printed exactly as written. A variable name without quotes is replaced by its current value. The + operator joins (concatenates) them into a single line of output.

Most useful programs follow the same three-step pattern:

1. Declare the variables you will need.
2. INPUT values from the user (with helpful prompts).
3. Process the data and OUTPUT the results.

Worked Example: Greeting the User

DECLARE Name : STRING

OUTPUT "What is your name? "
INPUT Name
OUTPUT "Hello, " + Name + " — welcome!"

If the user types Aisha, the program prints:

Hello, Aisha — welcome!

Worked Example: Doubling a Number

DECLARE N : INTEGER
DECLARE Doubled : INTEGER

OUTPUT "Enter a whole number: "
INPUT N
Doubled <- N * 2
OUTPUT "Double of " + N + " is " + Doubled

Here are three short but complete programs that bring together everything you have learned. Read each one carefully and try to predict the output before reading the explanation.

Example 1: Area of a Rectangle

DECLARE Length : REAL
DECLARE Width : REAL
DECLARE Area : REAL

OUTPUT "Enter the length: "
INPUT Length
OUTPUT "Enter the width: "
INPUT Width
Area <- Length * Width
OUTPUT "The area is " + Area

Two values are read in (Length and Width), multiplied, and the result is stored in Area before being displayed. Notice the variables are REAL because lengths can have decimal parts.

Example 2: Updating a Counter

DECLARE Counter : INTEGER

Counter <- 0
OUTPUT "Counter starts at " + Counter
Counter <- Counter + 1
Counter <- Counter + 1
OUTPUT "After two increases, Counter is " + Counter

This program prints Counter starts at 0 and then After two increases, Counter is 2. Each Counter <- Counter + 1 line adds 1 to the current value.

Example 3: Swapping Two Values

DECLARE A : INTEGER
DECLARE B : INTEGER
DECLARE Temp : INTEGER

A <- 5
B <- 9
Temp <- A
A <- B
B <- Temp
OUTPUT "A = " + A + ", B = " + B

To swap two values, you need a temporary variable (Temp). First save A into Temp, then move B into A, then move Temp (the original A) into B. After the swap, A is 9 and B is 5. The program prints A = 9, B = 5.

Let's recap the most important ideas from this topic before you tackle the Question Bank.