How do I take a random char element from an existing array and assign it to a new array? I have this code with a testing method but my code only returns an empty array instead of the chars expected.
public static char[] generateHiddenCode(Random rand, int numPositions, char[] symbols) {
char[] arrCode = new char[numPositions];
for (int i=0; i<arrCode.length; ++i) {
arrCode[i] = (char) rand.nextInt(symbols.length); }
return arrCode; }
Test:
private static void testGenerateHiddenCode() {
boolean error = false;
{ //"randomly" chooses 3 symbols from the list
//We know which 3 will be chosen since we set the seed
Random rand = new Random(123);
int numPositions = 3;
char [] symbols = {'A', 'B', 'C', 'D'};
char [] expected = {'C', 'A', 'D'};
char [] result = MasterMind.generateHiddenCode( rand, numPositions, symbols);
if ( !Arrays.equals( expected, result)) {
System.out.println("1) testGenerateHiddenCode expected: " + Arrays.toString(expected) + " result: " + Arrays.toString(result));
error = true;
}
}
if (error) {
System.out.println("testGenerateHiddenCode failed");
} else {
System.out.println("testGenerateHiddenCode passed");
}
}
There is only one change in generateHiddenCode() method everything else is correct, you were generating a number using rand and casting to char but you are supposed to generate a number from rand and get the character in symbol array present at generated index -
public static char[] generateHiddenCode(Random rand, int numPositions, char[] symbols) {
char[] arrCode = new char[numPositions];
for (int i = 0; i <
arrCode.length; ++i) {
// get char from
symbol array and assign to arrCode array
arrCode[i] =
symbols[ rand.nextInt(symbols.length)];
}
return arrCode;
}
How do I take a random char element from an existing array and assign it to...
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