Using the following method printPrimes() for questions a-f below
Prime.java
package net.chenyuhong.junitTest;
import java.awt.datatransfer.StringSelection;
import java.util.Scanner;
/**
* @Title: Prime.java
* @Package net.chenyuhong.junitTest
* @Description: 打印质数
* @author cyh [email protected]
* @date 2017-3-12 下午6:23:11
* @version V1.0
*/
public class Prime {
final static int MAXPRIMES = 50;
//如果一个数不能被它之前的任何素数整除,那么它自己也是一个素数（反证法，如果不是素数，则一定可以分解为若干素数的乘积，而这些素数一定比本身小）
public static String printPrimes(int n){
int curPrime; //当前被考虑的数
int numPrimes; //至今为止找到的质数个数
boolean isPrime; //curPrime 是否为质数
int [] primes = new int [MAXPRIMES]; // 质数列表
primes[0] = 2;
numPrimes = 1;
curPrime = 2;
while(numPrimes < n){
curPrime++;
isPrime = true;
for(int i = 0;i <= numPrimes-1;i++){
if(isDivisible(primes[i],curPrime)){
isPrime = false;
break;
}
}
if(isPrime){
primes[numPrimes] = curPrime;
numPrimes++;
}
}
String str = "Prime:";
for(int i = 0;i <= numPrimes-1;i++){ //打印所有的质数
str += "_"+primes[i];
}
System.out.println(str);
return str;
}
private static boolean isDivisible(int i, int curPrime) {
return curPrime%i == 0;
}
// public static void main(String[] args) {
////
//// Scanner in=new Scanner(System.in); //使用Scanner类定义对象
//// System.out.println("please input a integer number");
//// int n=in.nextInt(); //接收整型数据
// int i = 10;
// while(i >= 0){
// printPrimes(i);
// i--;
// }
//
//
// }
}
PrimeTest.java
package net.chenyuhong.junitTest;
import static org.junit.Assert.*;
import java.util.Arrays;
import java.util.Collection;
import java.util.Scanner;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
/**
* @Title: PrimeTest.java
* @Package net.chenyuhong.junitTest
* @Description:
* @author cyh [email protected]
* @date 2017-3-12 下午8:43:08
* @version V1.0
*/
@RunWith(Parameterized.class)
public class PrimeTest {
private String primeString;
private int n;
public PrimeTest(String primeString,int n){
this.primeString = primeString;
this.n = n;
}
@Parameters
public static Collection<Object[]> getData(){
return Arrays.asList(new Object[][]{
//
// {"Prime:_2_3_5_7_11_13_17_19_23_29",10},
// {"Prime:_2_3_5_7_11_13_17_19_23",9},
// {"Prime:_2_3_5_7_11_13_17_19",8},
// {"Prime:_2_3_5_7_11_13_17",7},
// {"Prime:_2_3_5_7_11_13",6},
// {"Prime:_2_3_5_7_11",5},
// {"Prime:_2_3_5_7",4},
{"Prime:_2_3_5",3},
// {"Prime:_2_3",2},
// {"Prime:_2",1},
});
}
@Test
public void testPrintPrimes() {
assertEquals(this.primeString,Prime.printPrimes(this.n));
}
}
Answer:
■ (a) Draw the control flow graph for the printPrimes() method
■ (b)
Make sure the value of MAXPRIMES equals 4, then there will be an out-of-array –bound fault when n = 5;
■ (c)
Let the parameter n = 0 or n = 1.
■ (d)
TR for node coverage:
{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16}
TR for edge coverage:
{(1,2),(2,3),(2,4),(3,5),(5,6),(5,7),(6,9)(6,8)(9,10),(10,5),(8,7),(7,11),(7,12),(11,13),(12,13),(13,2),(2,4),(4,15),(15,16),(16,4),(4,14)}
TR for prime path coverage:
{A(1,2,4,14),B(1,2,4,15,16),C(4,15,16,4),D(5,6,9,10,5),E(1,2,3,5,6,9,10),F(1,2,3,5,6,8,7,11,13),G(1,2,3,5,6,8,7,12,13),H(1,2,3,5,7,11,13),I(1,2,3,5,7,12,13),J(2,3,5,6,8,7,11,13,2),K(2,3,5,6,8,7,12,13,2),L(2,3,5,7,11,13,2),M(2,3,5,7,12,13,2)}
■ (e)
Using Junit and Eclemma to test the method and cover all prime paths above
1) Test Case : n = 1;
Test Path : [1,2,4,15,16,4,14]
Prime path covered: A,B,C
2) Test Case : n = 2;
Test Path : [1,2,3,5,6,9,10,5,7,11,13,2,4,15,16,4,14]
Prime path covered: A,B,C,D,E,H,I,L,M
3) Test Case : n = 3;
Test Path : ……
Prime path covered: A,B,C,D,E,F,G,H,I,J,K,L,M completely covered!
