[JAVA] 배열

/*1차원 배열*/
public class Test {
    public static void main(String[] args) throws Exception {
        int arr[]; //배열 변수 선언,int[] arr 가능
        arr = new int[10]; //배열 생성
        arr[0] = 1;
        arr[1] = 2;
        arr[2] = arr[0]+arr[1];
        System.out.println(arr[0]);
        System.out.println(arr[1]);
        System.out.println(arr[2]);
    }
}

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/*1차원 배열*/
public class Test {
    public static void main(String[] args) throws Exception {
        int arr[] = {1,2,3,4};
        System.out.println(arr[0]);
        System.out.println(arr[1]);
        System.out.println(arr[2]);
    }
}

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/*2차원 배열*/
public class Test {
    public static void main(String[] args) throws Exception {
        int arr[][] = new int[3][4]; //배열 변수 선언,생성
        arr[0][0] = 1;
        arr[1][1] = 2;
        arr[2][2] = arr[0][0]+arr[1][1];
        System.out.println(arr[0][0]);
        System.out.println(arr[1][1]);
        System.out.println(arr[2][2]);
    }
}

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/*2차원 배열*/
public class Test {
    public static void main(String[] args) throws Exception {
        int arr[][] = {{1,2,3,4},
                       {5,6,7,8},
                       {9,10,11,12}};
        System.out.println(arr[0][0]);
        System.out.println(arr[1][1]);
        System.out.println(arr[2][2]);
    }
}

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/*length:배열의 항목 수 알아내는 예시*/
public class Test {
    public static void main(String[] args) throws Exception {
        int arr1[] = {1,2,3,4};
        int arr2[][] = {{1,2,3,4},
                       {5,6,7,8},
                       {9,10,11,12}};
        System.out.println(arr1.length); //배열의 크기 알아냄
        System.out.println(arr2[0].length);
        System.out.println(arr2.length);
    }
}

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