public class JavaTest {
public static void main(String[] args) {
int[] ar = { 1, 2, 3, 4, 5, 6, 7 };
int sum = sumOfAry(ar);
System.out.println(sum);
}
static int sumOfAry(int[] ar) {
int sum = 0;
for (int i = 0; i < ar.length; i++) {
sum += ar[i];
}
return sum;
}
}
[Console]
28
static int[] makeNewIntAry(int len) {
int[] ar = new int[len];
return ar;
}
class A{
static int a;
static double b;
static char ch;
static String str;
static boolean flag;
}
public class JavaTest {
public static void main(String[] args) {
A a = new A();
System.out.println(A.a);
System.out.println(A.b);
System.out.println(A.ch);
System.out.println(A.str);
System.out.println(A.flag);
}
}
[Console]
0
0.0
'\u0000'
null
false
public class JavaPractice {
public static void main(String[] args) {
int[] ar = new int[10];
for (int i = 0; i < ar.length; i++) {
System.out.print(ar[i] + " ");
}
System.out.println();
String[] ar2 = new String[3];
for (int i = 0; i < ar2.length; i++) {
System.out.print(ar2[i] + " ");
}
}
}
[Console]
0 0 0 0 0 0 0 0 0 0
null null null
String[] strArr = {"abcdef", "abcdef", "abcdef"};
/*
String[] strArr = new String[3];
strArr[0] = "";
strArr[1] = "";
strArr[2] = "";
*/
Circle[] circleArr = {new Circle(10), new Circle(10)};
/*
Circle[] circleArr = new Circle[2];
circleArr[0] = new Circle(10);
circleArr[1] = new Circle(10);
*/
Rectangle[] recArr = { new Rectangle(10, 20), new Rectangle(10, 30) };
/*
Rectangle[] recArr = new Rectangle[2];
recArr[0] = new Rectangle(10, 20);
recArr[1] = new Rectangle(10, 30);
*/
public class StringTest {
public static void main(String[] args) {
// main()의 매개변수 : String[]
for (int i = 0; i < args.length; i++) {
System.out.println(args[i]);
}
} // end of main
}
for (int i = 0; i < args.length; i++) {
System.out.println(args[i] + " : " + (args[i].length());
}
public class JavaTest {
public static void main(String[] args) {
int[] ar = { 1, 2, 3, 4, 5 };
for (int e : ar) {
System.out.println(e);
}
/*
for (int i = 0; i < ar.length; i++) {
System.out.println(ar[i]);
}
*/
}
}
public class JavaTest {
public static void main(String[] args) {
int[] ar = { 1, 2, 3, 4, 5 };
int sum = 0;
for (int e : ar) {
sum += e;
}
System.out.println("sum : " + sum);
}
}
[Console]
sum : 15
public class JavaTest {
public static void main(String[] args) {
String[] ar = { "aaa", "bbbb", "c"};
int sum = 0;
for (String str : ar) {
sum += str.length();
}
System.out.println("문자열의 길이의 합 : " + sum);
}
}
[Console]
문자열의 길이의 합 : 8
class Box{
private int num;
private String str;
public Box(int num, String str){
this.num = num;
this.str = str;
}
public int getBoxNum() {
return num;
}
public String getBoxStr() {
return str;
}
}
public class JavaTest {
public static void main(String[] args) {
Box[] ar = new Box[5];
ar[0] = new Box(101, "Coffee");
ar[1] = new Box(202, "Computer");
ar[2] = new Box(303, "Apple");
ar[3] = new Box(404, "Dress");
ar[4] = new Box(505, "Fairy-tale book");
for(Box e:ar) {
if(e.getBoxNum() == 505) {
System.out.println(e.getBoxStr());
// System.out.println(e);
}
}
}
}
Box 클래스에 toString() 없을 때 : Box@4926097b
(Box의 주소값)
Box 클래스에 toString() 있을 때 : Fairy-tale book
(라이브러리에 있는 String 클래스가 overriding되면서 String 출력)