Table of Contents

• 1. Description
• 2. Syntax
  • 2.1. Stack Effect
• 3. Parameters
• 4. Return Values
• 5. Examples
  • 5.1. Basic Rounding
  • 5.2. Rounding to Decimal Places
• 6. Edge Cases
• 7. Related Commands
• 8. PostScript Level
• 9. Error Conditions
• 10. See Also

Returns the integer value nearest to a number.

1. Description

The round operator pops a number from the operand stack and pushes the integer value nearest to that number. If the number is equally close to two integers, round returns the greater of the two. The type of the result is the same as the type of the operand.

This is a Level 1 operator, available in all PostScript implementations.

2. Syntax

num1 round num2

2.1. Stack Effect

Table 1. Before Execution

Position	Content
Top	num1 (integer or real) - Number to round

Table 2. After Execution

Position	Content
Top	num2 (integer or real) - Rounded value (same type as num1)

3. Parameters

num1

Any number (integer or real)

4. Return Values

num2

The nearest integer value to num1 (type matches num1):

• For integers: returns the same value

• For reals: returns real with no fractional part, rounded to nearest

5. Examples

5.1. Basic Rounding

% Round to nearest integer
3.2 round      % → 3.0 (closer to 3)
3.7 round      % → 4.0 (closer to 4)

% Tie-breaking: 0.5 rounds to greater value
3.5 round      % → 4.0 (tie: chooses greater)
6.5 round      % → 7.0

% Negative numbers
-4.2 round     % → -4.0
-4.7 round     % → -5.0
-6.5 round     % → -6.0 (tie: chooses greater, less negative)

% Already integers
99 round       % → 99

5.2. Rounding to Decimal Places

% Round to n decimal places
/roundTo {  % value decimals -> rounded
    10 exch exp dup 3 1 roll mul round exch div
} def

3.14159 2 roundTo   % → 3.14
99.9876 1 roundTo   % → 100.0

6. Edge Cases

Ties (0.5) always round toward the greater value.

7. Related Commands

• ceiling - Round up

• floor - Round down

• truncate - Truncate toward zero

8. PostScript Level

Available in: PostScript Level 1 and higher

9. Error Conditions

stackunderflow

The operand stack is empty.

typecheck

The operand is not a number.

10. See Also

• Arithmetic and Math - All arithmetic operators