Detecting Overflow and Truncation in Integers

This lesson explains how overflow and truncation can be detected and prevented.

We'll cover the following

- Detecting overflow
  - Example
- Preventing overflow
  - Example
- Preventing truncation
  - Example

Detecting overflow #

Although detecting overflow uses functions, if conditions and ref parameters, which we have not covered yet, it should be mentioned here that the core.checkedint module contains arithmetic functions that detect overflow. Instead of operators like + and -, this module uses functions: adds and addu for signed and unsigned addition, muls and mulu for signed and unsigned multiplication, subs and subu for signed and unsigned subtraction and negs for negation.

Example #

Assume that a and b are two int variables, the following code can detect if adding them has caused an overflow:

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Getting Started With D

Variables and User Input

Arithmetic and Logical Operations on Data Types

Conditional Statements and Loops

Arrays, Characters and Strings

File Handling in D

Literals and enum

Formatted Output and Input

foreach Loop and switch-case Statement

Functions

Immutability

Value Types and Reference Types

Function Parameters

Program Environment

Exceptions and scope

assert and enforce Statements

Unit Testing

Contract Programming

Detecting Overflow and Truncation in Integers

Detecting overflow #

Example #