algorithm_basic_java/src/test/java/datastructure/stack/MyStackWithArrayTest.java at master · jbee37142/algorithm_basic_java · GitHub

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packagedatastructure.stack;

importorg.junit.Test;

importstaticorg.hamcrest.CoreMatchers.is;
importstaticorg.junit.Assert.assertThat;

publicclassMyStackWithArrayTest {

/*
 TASK
 Array를 사용하여 Stack을 구현한다.
 */

@Test
publicvoidtest() {
MyStackWithArraystack = newMyStackWithArray();

stack.push(0);
stack.push(1);
stack.push(2);
stack.push(3);
stack.push(4);
stack.push(5);
stack.push(6);

assertThat(stack.pop(), is(6));
assertThat(stack.pop(), is(5));
assertThat(stack.pop(), is(4));
assertThat(stack.pop(), is(3));
assertThat(stack.pop(), is(2));
assertThat(stack.pop(), is(1));
assertThat(stack.pop(), is(0));

// java.lang.RuntimeException: Empty Stack!
// assertThat(0, is(stack.pop()));
 }

publicclassMyStackWithArray {
privateint[] data = newint[5];
privateinttopIndex = -1;

publicsynchronizedvoidpush(inti) {
topIndex++;
if (topIndex >= data.length) {
int[] oldData = data;
data = newint[data.length * 2];
// System.arraycopy(oldData, 0, data, 0, oldData.length);
for (intj = 0; j < oldData.length; j++) {
data[j] = oldData[j];
 }
 }

data[topIndex] = i;
 }

publicsynchronizedintpop() {
if (topIndex < 0) {
thrownewRuntimeException("Empty Stack!");
 }
// int result = data[topIndex];
// topIndex--;
returndata[topIndex--];
 }
 }
}