homwork4——GraphCoverage第七题

Posted 2020-07-01

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/******************************************************* 
     * 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 (curPrime%primes[i]==0) 
                { // 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

题目代码如上，Method printPrimes()

（a）控制流图

技术分享

（b）当发生数组越界错误时，此时考虑测试用例 t1=(n=3) 和 t2=(n=5)则t2比t1更容易发现错误。

（c）当n=1时可以不通过while循环。

（d）

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

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

主路径覆盖:

[1,2,3,4,5,6,7]；

[1,2,3,5,6,8,9,11];

[1,2,3,5,6,8,9,10,11];

[1,2,3,5,9,11];

[1,2,3,5,9,10,11];

[1,2,12,13,14];

[1,2,12,13,15];

[3,4,5,6,8,9,10,11,2,12,13,14];

[3,4,5,6,8,9,10,11,2,12,13,15];

[3,4,5,6,8,9,11,2,12,13,14];

[3,4,5,6,8,9,11,2,12,13,15];