java基础（二）-数据类型

（1）java 数组属于引用类型，放在堆空间



public class Var {
public static void main(String args[]) {
int   a = 3;
float f = (float)3.14;   //强制转换
float f2 = 3.14f;

int i = 4;
short s = 4;
short s2 = (short)40000;  // 超过short类型，强制转换

//s = i;
s = (short)(s + 1);  
s = (short)(s + s2);

/* Java has no pointer */
//int* p = malloc(10*sizeof(int));
int p[] = new int[10];
int p2[] = {1,2,4}; /* static alloc */

//char str[100];
char str[] = new char[100];

//char str2[] = "abc";

String str2 = "abc";

p = null;
p2 = null;
str = null;
str2 = null;
}

}

public class Param {
public static void main(String args[]) {
int x = 1;
fun (x);  // 1

int p[] = new int[1];
p[0] = 123;

System.out.println("Before fun2: "+p[0]);
fun2(p);
System.out.println("After fun2: "+p[0]);  //200

System.out.println(x);
}

public static void fun(int x) {
x = 100;
}

public static void fun2(int[] p) {
p[0] = 200;
}

}