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Controls conditional branching. Statements in the if-block are executed only if the if-expression evaluates to a non-zero value (or TRUE). If the value of expression is nonzero, statement1 and any other statements in the block are executed and the else-block, if present, is skipped. If the value of expression is zero, then the if-block is skipped and the else-block, if present, is executed. Expressions that evaluate to non-zero are
- TRUE
- a non-null pointer,
- any non-zero arithmetic value, or
- a class type that defines an unambiguous conversion to an arithmetic, boolean or pointer type. (For information about conversions, see Standard Conversions.)
Syntax
Example
- C Nested if.else. The if.else statement executes two different codes depending upon whether the test expression is true or false. Sometimes, a choice has to be made from more than 2 possibilities. The nested if.else statement allows you to check for multiple test expressions and execute different codes for more than two conditions.
- I have 3 strings variables that user enter three words. And must the program sort them alphabetically what I tried to make it with if statement but the problem is if the user insert the first 5 chars are the same I am tired of repeating the code for every time.
if statement with an initializer
Jan 21, 2014 C Tutorial - 9 - using if else if statement PRABEESH R K. Unsubscribe from PRABEESH R K? C / if-else Statement - Duration: 29:24. Saif Bashar 16,777 views.
Visual Studio 2017 version 15.3 and later (available with /std:c++17): An if statement may also contain an expression that declares and initializes a named variable. Use this form of the if-statement when the variable is only needed within the scope of the if-block.
Example
In all forms of the if statement, expression, which can have any value except a structure, is evaluated, including all side effects. Control passes from the if statement to the next statement in the program unless one of the statements contains a break, continue, or goto.
The else clause of an if...else statement is associated with the closest previous if statement in the same scope that does not have a corresponding else statement.
if constexpr statements
Visual Studio 2017 version 15.3 and later (available with /std:c++17): In function templates, you can use an if constexpr statement to make compile-time branching decisions without having to resort to multiple function overloads. For example, you can write a single function that handles parameter unpacking (no zero-parameter overload is needed):
See also
Selection Statements
Keywords
switch Statement (C++)
- C Programming Tutorial
- C Programming useful Resources
- Selected Reading
An if statement can be followed by an optional else statement, which executes when the Boolean expression is false.
Syntax
The syntax of an if...else statement in C programming language is −
C++ If Else Statement Words Dev Hq 2017
If the Boolean expression evaluates to true, then the if block will be executed, otherwise, the else block will be executed.
C programming language assumes any non-zero and non-null values as true, and if it is either zero or null, then it is assumed as false value.
Flow Diagram
Example
When the above code is compiled and executed, it produces the following result −
If...else if...else Statement
An if statement can be followed by an optional else if...else statement, which is very useful to test various conditions using single if...else if statement.
When using if...else if..else statements, there are few points to keep in mind −
An if can have zero or one else's and it must come after any else if's.
An if can have zero to many else if's and they must come before the else.
Once an else if succeeds, none of the remaining else if's or else's will be tested.
Syntax
C++ If Else Statement Words Dev Hq Video
The syntax of an if...else if...else statement in C programming language is −
C++ If Else Statement Words Dev Hq Download
Example
When the above code is compiled and executed, it produces the following result −