National Instruments BridgeVIEW 用户手册
Chapter 12
Case and Sequence Structures and the Formula Node
12-2
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Case Structure
The Case structure has two or more subdiagrams, or cases, exactly one of
which executes when the structure executes. This depends on the value
of an integer, Boolean, string, or enum value you wire to the external side
of the selection terminal or selector. A Case structure is shown in the
following illustration.
which executes when the structure executes. This depends on the value
of an integer, Boolean, string, or enum value you wire to the external side
of the selection terminal or selector. A Case structure is shown in the
following illustration.
Note
Case statements in other programming languages generally do not execute any
case if a case is out of range. In G, you must either include a default case that
handles out-of-range values or explicitly list every possible input value.
case if a case is out of range. In G, you must either include a default case that
handles out-of-range values or explicitly list every possible input value.
Activity 12-1. Use the Case Structure
Your objective is to build a VI that checks a number to see if it is positive.
If the number is positive, the VI calculates the square root of the number;
otherwise, the VI returns an error.
If the number is positive, the VI calculates the square root of the number;
otherwise, the VI returns an error.
Front Panel
1.
Open a new front panel and create the objects as shown in the
following illustration.
following illustration.
The
Number
control supplies the number. The
Square Root Value
indicator displays the square root of the number. The free label acts as
a note to the user.
a note to the user.