String(字符串)的练习

小鱼儿 2021-11-14 14:28 340阅读 0赞

package com.qf.test;
    
    import com.qf.home.Goods;
    
    public class Test {
    
    	public static void main(String[] args) {
    		String s="akslskskskssk";
    		fun1(s);
    		fun12(s);
    		fanzhaun(s);
    		fanzhuan2(s);
    		fun3();
    		fun4();
    		fun41();
    		
    	}
    	
    	String s="how do you do",写一个方法使用此字串最后得到s1="od uoy od  nowoh"; 
    	//先反转在插入
    	public static void fun4() {
    		String s="how do you do";
    		StringBuilder sBuilder=new StringBuilder(s);
    		sBuilder.reverse();//反转方法
    		sBuilder.insert(sBuilder.indexOf("woh"), "no");//插入"no"字符串
    		System.out.println(sBuilder);
    	}
    	//先插入再反转
    	public static void fun41() {
    		String s="how do you do";
    		StringBuilder sBuilder=new StringBuilder(s);
    		sBuilder.insert(sBuilder.indexOf(" "), "on");
    		sBuilder.reverse();
    		System.out.println(sBuilder);
    		
    	}
    	
    	//String s="go home go home go home";使用StringBuilder在每一个go的后面添加一个" my";
    	//indexOf  insert
    	
    	public static void fun3() {
    		String s="go home go home go home";
    		StringBuilder sBuilder=new StringBuilder(s);
    		int index=0;
    		int count=1;
    		while(index!=-1) {
    			index = sBuilder.indexOf("go", index);
    			if(index!=-1) {
    				sBuilder.insert(index+2, " my");
    				index+=5*count;
    				count++;
    			}
    		}
    		System.out.println(sBuilder);
    	}
    	
    	//写一个方法，传入一个String，将String反转，不能使用reverse
    	//用第三个变量来交换
    	public static void fanzhaun(String string) {
    		char[] charArray = string.toCharArray();
    		for (int i = 0; i < charArray.length/2; i++) {
    			char c=charArray[i];
    			charArray[i]=charArray[charArray.length-1-i];
    			charArray[charArray.length-1-i]=c;
    		}
    		System.out.println(new String(charArray));
    	}
    	//两个数组  后一个数组的第一个存放前一个数组的最后一个      循环
    	public static void fanzhuan2(String string) {
    		char[] charArray = string.toCharArray();
    		char[] cs=new char[charArray.length];
    		for (int i = 0; i < charArray.length; i++) {
    			cs[i]=charArray[charArray.length-1-i];
    		}
    		System.out.println(new String(cs));
    	}
    	
    	//String s="akslskskskssk",使用方法来获取k出现的次数，以及每一次出现的具体位置
    	
    	//toCharArray()   indexOf()   
    	public static void fun12(String string) {
    		char[] charArray = string.toCharArray();
    		int count=0;
    		int index=0;
    		while (index!=-1) {
    			index= string.indexOf('k', index);
    			if(index!=-1) {
    				count++;
    				System.out.println("第"+count+"出现的位置===="+index);
    				index++;
    			}
    		}
    		System.out.println("出现的次数:"+count);
    	}
    	
    	public static void fun1(String string) {
    		char[] charArray = string.toCharArray();
    		int count=0;
    		for (int i = 0; i < charArray.length; i++) {
    			if (charArray[i]=='k') {
    				count++;
    				System.out.println("第"+count+"出现的位置"+i);
    			}
    		}
    		System.out.println("出现的次数:"+count);
    	}
    	
    }