Use the following method printPrimes() for questions a-d (inside the textbook)

Posted 2020-09-04

1. Codes from the textbook

/*******************************************************
* 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 [n]; // 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

 

static boolean isDivisible(int x, int y){

int a = y/x;

double b = (double)y/(double)x;

// System.out.println(a);

// System.out.println(b);

if(b-a == 0){

return true;

}

else{

return false;

}

}

 

2. Control flow graph

2. For instance, when the greatest prime is below 4, n=5 is in front of n = 3

3. When n < 2, the while loop will not be executed.

4. Point Coverage: {1,2,3,4,5,6,7,4,7,8,9,10,11}

Edge Coverage: {{1,2},{2,3},{3,4},{4,7},{4,5},{5,4},{5,6},{6,7},{7,8},{7,2},{8,2},{2,9},{9,10},{10,9},{9,11}}

Main Path Coverage: {（1,2,3,4,5,6,8），（1,2,3,4,5,6,7,9,10），（1,2,3,4,5,6,7,9），（1,2,3,4,5,9,10），（1,2,3,4,5,9），（3,4,5,6,7,9,10,2,11），（3,4,5,6,7,9,2,11），（3,4,5,6,7,9,10,2,11），（3,4,5,6,7,9,2,11），（3,4,5,9,10,2,11），（3,4,5,9,2,11），（3,4,5,9,10,2,11），（3,4,5,9,2,11），（6,8,5,9,10,2,11），（6,8,5,9,2,11），（6,8,5,9,10,2,11），（6,8,5,9,2,11），（5,6,8,5），（2,3,4,5,6,7,9,10,2），（2,3,4,5,6,7,9,2），（2,3,4,5,9,10,2），（2,3,4,5,9,2）}

 

5. Test the Main Path Coverage based on Junit and Eclemma

Set n=2 in path1 and set n=5 in path2