mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-28 13:50:10 +01:00
Aadarsh Raj
4e9e43a109
**### There is issue in conditionals.md readme file**
**In example of fruits conditionals**
**there are fruits.IsGreen() if it is False then continue.
if it is True then print "Apple" but in readme file there is "Orange"**
I replaced "Orange" with "Apple" because in example there is "Apple"
```carbon
if (fruit.IsYellow()) {
Print("Banana!");
} else if (fruit.IsOrange()) {
Print("Orange!");
} else if (fruit.IsGreen()) {
Print("Apple!");
} else {
Print("Vegetable!");
}
fruit.Eat();
```
85 lines
2.4 KiB
Markdown
85 lines
2.4 KiB
Markdown
# Conditionals
|
|
|
|
<!--
|
|
Part of the Carbon Language project, under the Apache License v2.0 with LLVM
|
|
Exceptions. See /LICENSE for license information.
|
|
SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
-->
|
|
|
|
<!-- toc -->
|
|
|
|
## Table of contents
|
|
|
|
- [Overview](#overview)
|
|
- [Alternatives considered](#alternatives-considered)
|
|
- [References](#references)
|
|
|
|
<!-- tocstop -->
|
|
|
|
## Overview
|
|
|
|
`if` and `else` provide conditional execution of statements. Syntax is:
|
|
|
|
> `if (`_boolean expression_ `) {` _statements_ `}`
|
|
>
|
|
> [ `else if (` _boolean expression_ `) {` _statements_ `}` ] ...
|
|
>
|
|
> [ `else {` _statements_ `}` ]
|
|
|
|
Only one group of statements will execute:
|
|
|
|
- When the first `if`'s boolean expression evaluates to true, its associated
|
|
statements will execute.
|
|
- When earlier boolean expressions evaluate to false and an `else if`'s
|
|
boolean expression evaluates to true, its associated statements will
|
|
execute.
|
|
- `... else if ...` is equivalent to `... else { if ... }`, but without
|
|
visible nesting of braces.
|
|
- When all boolean expressions evaluate to false, the `else`'s associated
|
|
statements will execute.
|
|
|
|
When a boolean expression evaluates to true, no later boolean expressions will
|
|
evaluate.
|
|
|
|
Note that `else if` may be repeated.
|
|
|
|
For example:
|
|
|
|
```carbon
|
|
if (fruit.IsYellow()) {
|
|
Print("Banana!");
|
|
} else if (fruit.IsOrange()) {
|
|
Print("Orange!");
|
|
} else if (fruit.IsGreen()) {
|
|
Print("Apple!");
|
|
} else {
|
|
Print("Vegetable!");
|
|
}
|
|
fruit.Eat();
|
|
```
|
|
|
|
This code will:
|
|
|
|
- Evaluate `fruit.IsYellow()`:
|
|
- When `True`, print `Banana!` and resume execution at `fruit.Eat()`.
|
|
- When `False`, evaluate `fruit.IsOrange()`:
|
|
- When `True`, print `Orange!` and resume execution at `fruit.Eat()`.
|
|
- When `False`, evaluate `fruit.IsGreen()`:
|
|
- When `True`, print `Apple!` and resume execution at
|
|
`fruit.Eat()`.
|
|
- When `False`, print `Vegetable!` and resume execution at
|
|
`fruit.Eat()`.
|
|
|
|
## Alternatives considered
|
|
|
|
- [Optional braces](/proposals/p0623.md#optional-braces)
|
|
- [Optional parentheses](/proposals/p0623.md#optional-parentheses)
|
|
- [`elif`](/proposals/p0623.md#elif)
|
|
|
|
## References
|
|
|
|
- Proposal
|
|
[#285: `if` and `else`](https://github.com/carbon-language/carbon-lang/pull/285)
|
|
- Proposal
|
|
[#623: Require braces](https://github.com/carbon-language/carbon-lang/pull/623)
|