If statements

While coding, we often want certain pieces of code to be executed only if some condition is true. Like "if the moment load bearing capacity is exceeded for this member, then increase the cross-section height". In this example, the "moment load bearing capacity is exceeded" is the condition, and the "increase the cross-section height" is the conditionally executed statement.

For this purpose, the if statement is implemented in Descript.

Syntax

if [Condition]
        // Place for the conditionally executed code
endif

Syntax explanation

Any code that is put between the if and the endif keywords constitutes the body of the if statement and will be executed only if the condition evaluates to true.

This is the syntax for the so-called one-way if statement, where if the condition evaluates to true, the code in if statement will be executed, otherwise nothing happens.

If-else statement

We can also expand the if statement with an "else" branch. If we do this, we will get a two-way if statement, where we can have different pieces of code executing, if the condition evaluates to true, or false.

If-else syntax

if [Condition]
        // Code executed if condition is true
else
        // Code executed if condition is false
endif

Condition

In Descript, the condition of the if statement is always a comparison of two values with an operator between them.

In the condition expression, between the two compared values the following operators can be used:

Operator	Meaning
==	Equal
!=	Unequal
<	Less than
<=	Less than or equal
>	Greater than
>=	Greater than or equal

Sample code

If statement: (Simplest form, one-way if statement)

if $n > 1
    // Conditionally executed code
endif

If-else statement: (two-way if statement)

if $n > 1
    // Code if condition evaluates to true
else
    // Code if condition evaluates to false
endif

Example 1:

if $Start_Analysis == 1

    ANALYSIS RUN
    Type Elastic
    LoadCombinations "NAME: Load Combination-1"
    FirstOrder

endif

In this example, if the $Start_Analysis variable is equal to 1, then an ANALYSIS RUN command will be executed, otherwise nothing happens.

Example 2:

if $Buckling_Analysis == 1

    ANALYSIS RUN
    Type Elastic
    LoadCombinations "NAME: Load Combination-1"
    FirstOrder
    Buckling 10

else

    ANALYSIS RUN
    Type Elastic
    LoadCombinations "NAME: Load Combination-1"
    FirstOrder

endif

In this example, if the $Buckling_Analysis variable is equal to 1, then an ANALYSIS RUN command will be executed with a buckling analysis, otherwise an ANALYSIS RUN command will be executed with only a first order analysis and no buckling analysis.