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sav08:proving_correctness_of_some_small_examples [2008/02/17 18:38]
vkuncak
sav08:proving_correctness_of_some_small_examples [2010/02/22 12:16]
vkuncak
Line 1: Line 1:
 ====== Proving Correctness of Some Small Examples ====== ====== Proving Correctness of Some Small Examples ======
  
-In this demo we go through several examples and prove them correct using Jahob.+In this demo we go through several examples and prove them correct using the [[:Jahob system]].
  
 ==== A Recursive Function ==== ==== A Recursive Function ====
Line 7: Line 7:
 Consider the following recursive function: Consider the following recursive function:
  
-<​code ​java>+<​code>​
 private static int f(int x, int y) private static int f(int x, int y)
 { {
Line 22: Line 22:
 } }
 </​code>​ </​code>​
 +
 +  * What does '​f'​ compute?
 +  * How can we prove it?
 +  * [[Proof of first lecture01 example]]
 +
 +=== An Iterative Example ===
 +
 +<​code>​
 +private static int fi(int x, int y)
 +{
 +  int r = 0;
 +  int i = 0;
 +  while
 +    (i < y) {
 +    i = i + 1;
 +    r = r + x;
 +  }
 +  return r;
 +}
 +</​code>​
 +
 +  * How can we prove it?
 +  * [[Notion of inductive loop invariant]]
 +  * What is and is not inductive loop invariant in this example
 +
 +=== Transforming iterative version ===
 +
 +  * changing initial condition
 +
 +=== Summary of these Small Examples ===
  
 {{sav08:​integerdemo.java.txt|Examples of Functions with Specifications}} {{sav08:​integerdemo.java.txt|Examples of Functions with Specifications}}
  
-For homework, you will have more such examples.+=== Some other Examples done in Jahob === 
 + 
 +  * http://​javaverification.org/ 
 + 
 +=== Another System ===
  
 +  * [[http://​research.microsoft.com/​en-us/​projects/​vcc|VCC:​ A Verifier for Concurrent C]]