题目代码如下：
1 /*******************************************************
2 * Finds and prints n prime integers
3 * Jeff Offutt, Spring 2003
4 ******************************************************/
5 public static void printPrimes (int n)
6 {
7 int curPrime; // Value currently considered for primeness
8 int numPrimes; // Number of primes found so far.
9 boolean isPrime; // Is curPrime prime?
10 int [] primes = new int [MAXPRIMES]; // The list of prime numbers.
11
12 // Initialize 2 into the list of primes.
13 primes [0] = 2;
14 numPrimes = 1;
15 curPrime = 2;
16 while (numPrimes < n)
17 {
18 curPrime++; // next number to consider ...
19 isPrime = true;
20 for (int i = 0; i <= numPrimes-1; i++)
21 { // for each previous prime.
22 if (curPrime%primes[i]==0)
23 { // Found a divisor, curPrime is not prime.
24 isPrime = false;
25 break; // out of loop through primes.
26 }
27 }
28 if (isPrime)
29 { // save it!
30 primes[numPrimes] = curPrime;
31 numPrimes++;
32 }
33 } // End while
34
35 // Print all the primes out.
36 for (int i = 0; i <= numPrimes-1; i++)
37 {
38 System.out.println ("Prime: " + primes[i]);
39 }
40 } // end printPrimes
a.控制流图如下：
b.设计一个t2=(n=5)比t1=(n=3)更容易发现的错误。容易想到数组越界，即当 MAXPRIMES = 3 or 4 时，t1正常通过，而t2会因越界而报错。
c.显然当 n = 1 时不会经过while循环。
d.找出所有点覆盖、边覆盖和主路径覆盖的TR。
点覆盖：{ 1,2,3,4,5,6,7,8,9,10,11,12,13 }
边覆盖：{ (1,2), (2,3), (2,10), (3,4), (4,5), (4,8)，(5,6), (5,7), (7,4), (6,8), (8,9), (8,2), (9,2), (10,11), (11,12), (11, 13), (12,11) }
主路径覆盖：{ (1,2,3,4,8,2,10,11,13), (1,2,3,4,8,2,10,11,12,11,13), (1,2,3,4,8,9,2,10,11,13), (1,2,3,4,8,9,2,10,11,12,11,13),
(1,2,3,4,5,6,8,2,10,11,13), (1,2,3,4,5,6,8,2,10,11,12,11,13), (1,2,3,4,5,6,8,9,2,10,11,13), (1,2,3,4,5,6,8,9,2,10,11,12,11,13),
(3,4,5,6,8,9,10,11,2,12,13), (3,4,5,6,8,9,11,2,12,13), (3,4,5,6,8,9,10,11,2,12,13), (4,5,7,4), (11,12,11), (2,3,4,8,2), (2,3,4,8,9,2),
(2,3,4,5,6,8,9,2)... }
e.对上次的三角形判定程序设计主路径覆盖的测试用例。
1 //Triangle.java
2 import java.util.Arrays;
3
4 public class Triangle
5 {
6 public String check( String p, String q, String r )
7 {
8 int[] a = new int[3];
9 a[0] = Integer.parseInt(p);
10 a[1] = Integer.parseInt(q);
11 a[2] = Integer.parseInt(r);
12 Arrays.sort(a);
13 if ( a[0] + a[1] > a[2] )
14 {
15 if ( a[0] == a[2] )
16 {
17 return "equilateral";
18 }
19 else
20 {
21 if ( a[0] == a[1] || a[1] == a[2] )
22 {
23 return"isosceles";
24 }
25 else
26 {
27 return "scalene";
28 }
29 }
30 }
31 else
32 {
33 return "not a triangle";
34 }
35 }
36 }
1 import static org.junit.Assert.*;
2 import java.util.Arrays;
3 import java.util.Collection;
4 import org.junit.Before;
5 import org.junit.Test;
6 import org.junit.runner.RunWith;
7 import org.junit.runners.Parameterized;
8 import org.junit.runners.Parameterized.Parameters;
9
10 @RunWith(Parameterized.class)
11 public class TriangleTest
12 {
13 private String p;
14 private String q;
15 private String r;
16 private String expected;
17 private Triangle tmp;
18
19 public TriangleTest( String p, String q, String r, String expected )
20 {
21 this.p = p;
22 this.q = q;
23 this.r = r;
24 this.expected = expected;
25 }
26
27 @Before
28 public void setUp()
29 {
30 tmp = new Triangle();
31 }
32
33 @Parameters
34 public static Collection<String[]> getData()
35 {
36 return Arrays.asList( new String[][]
37 {
38 { "3", "3", "3", "equilateral" },
39 { "3", "4", "4", "isosceles" },
40 { "3", "4", "5", "scalene" },
41 { "3", "4", "7", "not a triangle" },
42 });
43 }
44
45 @Test
46 public void test()
47 {
48 assertEquals( this.expected, tmp.check( p, q, r ) );
49 }
50 }
测试用例见：@Parameters部分。
可见覆盖率达到了100%。
