java类型学习

 

一个java文件中，有且只有一个public类

float ff= 1.3f;(4B)

int 4B;

long 8B;

double 8B;

byte 一字节整型

char 2B

 

数组

int num[] = new int[3];

int[] num;

num = new int[3];

int [] num = new int[]{1,2,3};

int [][] num;

num = new int[3][4];

//不同长

num = new int[3][];

num[0] = new int[5];

num[1] = new int[3];

....

 

int [][] num = new int[][]{{1,2}, {3,4,5}};

int [][] num = {{...}, {...}};