What is the format of if statement in C language?

#What is the format of if statement in c language?

The format of if statement in c language:

3 forms

1. The first form is the basic form: if

if (expression) statement

The semantics are: if the value of the expression is true, the following statement will be executed, otherwise the statement will not be executed.

2. The second form is: if-else

if (expression) statement 1;else statement 2;

The semantics is: if the value of the expression If it is true, statement 1 is executed, otherwise statement 2 is executed.

3. The third form is if-else-if form

The first two forms of if statements are generally used in two-branch situations. When there are multiple branch choices, if-else-if statements can be used.

The general form is: if (expression 1) statement 1; else if (expression 2) statement 2; else if (expression Formula 3) Statement 3;…

else if (expression m) statement m; else statement n;

The semantics is: judge the value of the expression in turn, when a certain value appears When true, the corresponding statement is executed. Then jump outside the entire if

statement and continue executing the program. If all expressions are false, statement n is executed. Then continue with subsequent procedures.

Extended information

You should also pay attention to the following issues when using if statements:

Among the three forms of if statements, in The if keyword is followed by expressions.

The expression is usually a logical expression or a relational expression, but it can also be other expressions, such as assignment expressions, etc., or even a variable. For example: if(a=5) statement; if(b) statement;

are all allowed. As long as the value of the expression is non-zero, it is "true". For example: if(a=5)...; the value of the expression is always non-0, so the following statements will always be executed. Of course, this situation may not appear in the program, but it is grammatically legal. of.

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