Rust: Clean up the UnusedValue examples.

Author: geoffw0

rust/ql/src/queries/unusedentities/UnusedValue.qhelp

@@ -14,7 +14,7 @@
 <example>
 <p>In the following example, there is a variable <code>average</code> that is initialized to <code>0</code>, but that value is never used:</p>
 <sample src="UnusedValueBad.rs" />
-<p>The problem can be fixed by removing the value and the variable that contains it:</p>
+<p>The problem can be fixed by removing the unused value:</p>
 <sample src="UnusedValueGood.rs" />
 </example>
 

rust/ql/src/queries/unusedentities/UnusedValueBad.rs

@@ -1,11 +1,11 @@
-fn get_average(values:&[i32]) -> i32 {
+fn get_average(values:&[i32]) -> f64 {
 	let mut sum = 0;
-	let mut average = 0; // BAD: unused value
+	let mut average = 0.0; // BAD: unused value
 
 	for v in values {
 		sum += v;
 	}
 
-        average = sum / values.len();
+	average = sum as f64 / values.len() as f64;
 	return average;
 }

rust/ql/src/queries/unusedentities/UnusedValueGood.rs

@@ -1,9 +1,11 @@
-fn get_sum(values:&[i32]) -> i32 {
+fn get_average(values:&[i32]) -> f64 {
 	let mut sum = 0;
+	let average;
 
 	for v in values {
 		sum += v;
 	}
 
-	return sum;
+	average = sum as f64 / values.len() as f64;
+	return average;
 }