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| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
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sav08:forward_vcg [2010/03/09 17:18] vkuncak |
sav08:forward_vcg [2010/03/09 17:22] vkuncak |
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| - | ===== Example ===== | ||
| + | |||
| + | ===== Examples ===== | ||
| + | |||
| + | **Example 1.** | ||
| Precondition: $\{x \ge 5 \wedge y \ge 3\}$. Code: | Precondition: $\{x \ge 5 \wedge y \ge 3\}$. Code: | ||
| <code> | <code> | ||
| Line 102: | Line 105: | ||
| \leftrightarrow \ y \ge 3 \land x \ge y + 15 | \leftrightarrow \ y \ge 3 \land x \ge y + 15 | ||
| \end{array} | \end{array} | ||
| + | \] | ||
| + | |||
| + | **Example 2** Precondition: $\{x \ge 2 \land y \le 5 \land x \le y \}$. Code: | ||
| + | <code> | ||
| + | havoc(x) | ||
| + | </code> | ||
| + | |||
| + | \[ | ||
| + | \exists x_0.\ x_0 \ge 2 \land y \le 5 \land x_0 \le y | ||
| + | \] | ||
| + | i.e. | ||
| + | \[ | ||
| + | \exists x_0.\ 2 \le x_0 \le y \land y \le 5 | ||
| + | \] | ||
| + | i.e. | ||
| + | \[ | ||
| + | 2 \le y \land y \le 5 | ||
| \] | \] | ||