Movatterモバイル変換


[0]ホーム

URL:


Menu
×
See More 
Sign In
+1 Get Certified Upgrade Teachers Spaces Get Certified Upgrade Teachers Spaces
   ❮     
     ❯   

C++ Tutorial

C++ HOMEC++ IntroC++ Get StartedC++ SyntaxC++ OutputC++ CommentsC++ VariablesC++ User InputC++ Data TypesC++ OperatorsC++ StringsC++ MathC++ BooleansC++ If...ElseC++ SwitchC++ While LoopC++ For LoopC++ Break/ContinueC++ ArraysC++ StructuresC++ EnumsC++ ReferencesC++ PointersC++ MemoryManagement

C++ Functions

C++ FunctionsC++ Function ParametersC++ Function OverloadingC++ ScopeC++ RecursionC++ Lambda

C++ Classes

C++ OOPC++ Classes/ObjectsC++ Class MethodsC++ ConstructorsC++ Access SpecifiersC++ EncapsulationC++ Friend FunctionsC++ InheritanceC++ PolymorphismC++ TemplatesC++ FilesC++ Date

C++ Errors

C++ ErrorsC++ DebuggingC++ ExceptionsC++ Input Validation

C++ DataStructures

C++ Data Structures & STLC++ VectorsC++ ListC++ StacksC++ QueuesC++ DequeC++ SetsC++ MapsC++ IteratorsC++ Algorithms

C++ Namespaces

C++ Namespaces

C++ Projects

C++ Projects

C++ How To

C++ Add Two NumbersC++ Random Numbers

C++ Reference

C++ ReferenceC++ KeywordsC++ <iostream>C++ <fstream>C++ <cmath>C++ <string>C++ <cstring>C++ <ctime>C++ <vector>C++ <algorithm>

C++ Examples

C++ ExamplesC++ Real-Life ExamplesC++ CompilerC++ ExercisesC++ QuizC++ SyllabusC++ Study PlanC++ Certificate


C++If ... Else Examples


Real Life Example

This example shows how you can useif..else to "open a door" if the user enters the correct code:

Example

int doorCode = 1337;

if (doorCode == 1337) {
  cout << "Correct code.\nThe door is now open.\n";
} else {
  cout << "Wrong code.\nThe door remains closed.\n";
}
Try it Yourself »

This example shows how you can useif..else to find out if a number is positive or negative:

Example

int myNum = 10; // Is this a positive or negative number?

if (myNum > 0) {
  cout << "The value is a positive number.\n";
} else if (myNum < 0) {
  cout << "The value is a negative number.\n";
} else {
  cout << "The value is 0.\n";
}
Try it Yourself »

Find out if a person is old enough to vote:

Example

int myAge = 25;
int votingAge = 18;

if (myAge >= votingAge) {
  cout << "Old enough to vote!\n";
} else {
  cout << "Not old enough to vote.\n";
}
Try it Yourself »

Find out if a person is old enough to vote,andif they are a citizen (using nested if statements):

Example

int age = 20;bool isCitizen = true;if (age >= 18) {  cout << "Old enough to vote.\n";  if (isCitizen) {    cout << "And you are a citizen, so you can vote!\n";  } else {    cout << "But you must be a citizen to vote.\n";  }} else {  cout << "Not old enough to vote.\n";}

Try it Yourself »

Find out if a number is even or odd:

Example

int myNum = 5;

if (myNum % 2 == 0) {
  cout << myNum << " is even.\n";
} else {
  cout << myNum << " is odd.\n";
}
Try it Yourself »

Check temperature (Celsius):

Example

int temperature = 30; if (temperature < 0) {  cout << "It's freezing!\n";} else if (temperature < 20) {  cout << "It's cool.\n";} else {  cout << "It's warm.\n";}
Try it Yourself »


×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
sales@w3schools.com

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
help@w3schools.com

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning.
Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness
of all content. While using W3Schools, you agree to have read and accepted ourterms of use,cookies andprivacy policy.

Copyright 1999-2025 by Refsnes Data. All Rights Reserved.W3Schools is Powered by W3.CSS.


[8]ページ先頭

©2009-2025 Movatter.jp