# Variable computational use

De Software testing

## Concepts

- A variable computational use is the use of a variable within an expression as part of an assignment statement, in an output statement, as a parameter within a function call, and in subscript expressions. <bib>mathur:2008, 456</bib>

## Facts

- A variable computational use is called of c-use. <bib>vincenzi-etal:2007</bib>, <bib>mathur:2008, 456</bib>

- A variable computational use is associated with a node. <bib>vincenzi-etal:2007</bib>

- A variable computational use directly affects the computation being performed or allows the result from a previous variable definition to be observed. <bib>vincenzi-etal:2007</bib>

- Let z be a node in definition-computational use pair set of the variable x defined at the node q. Suppose that program P is executed against test case t and the complete path transversed is <math>p = (n_{1}, n_{i_{1}}, ..., n_{i_{l}}, n_{i_{l}+1}, ..., n_{i_{m}}, n_{i_{m}+1}, ..., n_{k})</math>, where <math>2 <= i_{j} < k for 1 <= j <= k</math>. This computational use of the variable x is considered covered if <math>q = n_{i_{1}}<math> and <math>s = n_{i_{m}}</math>, and the path <math>(n_{i_{j}}, n_{i_{j} + 1}, ..., n_{i_{m}})</math> is a definition-clear path from node q to node z. <bib>mathur:2008, 468</bib>

- All computational uses of a variable x are considered covered if each node in the definition-computation use pair set of x defined in node q is covered during one or more executions of P. <bib>mathur:2008, 468</bib>

- All computational uses in the program are considered covered if all computational uses of all variables in P are covered. <bib>mathur:2008, 468-469</bib>