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PrintPrimes

时间:2017-03-17 23:18:43      阅读:184      评论:0      收藏:0      [点我收藏+]

标签:nts   sys   div   bre   img   break   not   连接   ++   

/******************************************************* 
     * Finds and prints n prime integers 
     * Jeff Offutt, Spring 2003 
     ******************************************************/ 
    public static void printPrimes (int n) 
    { 
        int curPrime; // Value currently considered for primeness 
        int numPrimes; // Number of primes found so far. 
        boolean isPrime; // Is curPrime prime? 
        int [] primes = new int [MAXPRIMES]; // The list of prime numbers. 
        
        // Initialize 2 into the list of primes. 
        primes [0] = 2; 
        numPrimes = 1; 
        curPrime = 2; 
        while (numPrimes < n) 
        { 
            curPrime++; // next number to consider ... 
            isPrime = true; 
            for (int i = 0; i <= numPrimes-1; i++) 
            { // for each previous prime. 
                if (isDivisible(primes[i], curPrime)) 
                { // Found a divisor, curPrime is not prime. 
                    isPrime = false; 
                    break; // out of loop through primes. 
                } 
            } 
            if (isPrime) 
            { // save it! 
                primes[numPrimes] = curPrime; 
                numPrimes++; 
            } 
        } // End while 
        
        // Print all the primes out. 
        for (int i = 0; i <= numPrimes-1; i++) 
        { 
            System.out.println ("Prime: " + primes[i]); 
        } 
    } // end printPrimes

(a)绘制控制流图如下

技术分享

(b)设计一个简单的错误,使得t2(n=5)比t1(n=3)更容易发现。

较容易发生的为数组越界错误。当MAXPRIMES为4时,t2会越界。

(c)找到一个测试用例,使得相应的测试路径访问连接while语句开始到for语句的边,而不通过while循环体。

当n=1时,即可满足要求。

(d)点覆盖:{1,2,3,4,5,6,7,5,6,8,9,10,11,12,13,14,15,16}

 边覆盖:{(1,2),(2,3),(2,12),(3,4),(4,5),(5,6),(6,7),(6,8),(7,5),(8,9), (5,9),(9,10),(9,11),(10,11),(11,2),(12,13),(13,14),(14,15),(15,13), (13,16)}

 主路径覆盖:{(1,2,3,4,5,6,7),(1,2,3,4,5,6,8,9,10,11),(1,2,3,4,5,6,8,9,11),(1,2,3,4,5,9,10,11),(1,2,3,4,5,9,11),(1,2,12,13,14,15),(1,2,12,16),(3,4,5,6,8,9,10,11,2,12,13,14,15),

 (3,4,5,6,8,9,11,2,12,13,14,15),(3,4,5,6,8,9,10,11,2,12,13,16),(3,4,5,6,8,9,11,2,12,13,16),(3,4,5,9,10,11,2,12,13,14,15),(3,4,5,9,11,2,12,13,14,15),(3,4,5,9,10,11,2,12,13,16),

 (3,4,5,9,11,2,12,13,16),(6,7,5,9,10,11,2,12,13,14,15),(6,7,5,9,11,2,12,13,14,15),(6,7,5,9,10,11,2,12,13,16),(6,7,5,9,11,2,12,13,16),(14,15,13,16),(13,14,15,13),(5,6,7,5),

 (2,3,4,5,6,8,9,10,11,2),(2,3,4,5,6,8,9,11,2),(2,3,4,5,9,10,11,2),(2,3,4,5,9,11,2)}

package primes;

public class Main {

    /*public static void main(String[] args){
        System.out.println(printPrimes(20));
    }*/
    public static String printPrimes(int n){ 
        int max=100;
        int curPrime; 
        int numPrimes; 
        boolean isPrime; 
        String result = "";
        int [] primes = new int [max];      
        primes[0] = 2; 
        numPrimes = 1; 
        curPrime = 2; 
        while (numPrimes < n){ 
           curPrime++; 
           isPrime = true; 
           for (int i = 0; i <= numPrimes-1; i++) 
           { 
               if (curPrime%primes[i]==0) 
               { 
                   isPrime = false; 
                   break; 
               } 
           } 
           if (isPrime) 
           {
               primes[numPrimes] = curPrime; 
               numPrimes++; 
           } 
        }
        for (int i = 0; i <= numPrimes-1; i++) { 
           result += primes[i]+" "; 
        }
        return result;
   }
}
package primes;

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class Maintest {
    String result;
    
    @Test
    public void test1(){
        result = Main.printPrimes(10);
        assertEquals("2 3 5 7 11 13 17 19 23 29 ",result);
    }
    @Test
    public void test2(){
        result = Main.printPrimes(20);
        assertEquals("2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 ",result);
    }
}

 

PrintPrimes

标签:nts   sys   div   bre   img   break   not   连接   ++   

原文地址:http://www.cnblogs.com/yitiaoxianyu/p/6569096.html

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