insertdeletedemo.java

本java源程序包括了大量的学习程序（共27章）方便大家学习

public class InsertDeleteDemo 
{
	public static void main(String[] args) 
	{
		String str = "Hello";
		//声明并初始化字符串对象str
		char ch[] = {'a','b','c','d','e','f','g'};
		//声明并初始化字符数组ch
		boolean b = true;
		//声明并初始化布尔型变量b
		int a = 10000;
		//声明并初始化整型变量a
		float f = 24.24f;
		//声明并初始化单精度变量f
		double d = 33.3333;
		//声明并初始化双精度变量d
		StringBuffer buffer = new StringBuffer();
		//声明并初始化可变字符串对象buffer
		buffer.insert(0,d); 
		//使用StringBuffer类中insert()方法，向buffer第0个位置插入各种类型值
		buffer.insert(0," ");
		buffer.insert(0,f);
		buffer.insert(0," ");
		buffer.insert(0,a);
		buffer.insert(0," ");
		buffer.insert(0,b);
		buffer.insert(0," ");
		buffer.insert(0,ch);
		buffer.insert(0," ");
		buffer.insert(0,str);
		System.out.println(buffer.toString()+"\n");
		buffer.deleteCharAt(6);
		//使用StringBuffer类中deleteCharAt()方法，删除buffer中第6个位置的字符
		System.out.println(buffer.toString()+"\n");
		buffer.delete(5,12);
		//使用StringBuffer类中delete()方法，删除buffer中第5个位置至第11位置之间的字符
		System.out.println(buffer.toString()+"\n");
	}

}