package com.Test;
public class ControlString {
public void First_toUpper(){
/*给出一句英文句子：“let there be light”
* 得到一个新的字符串，每个单词的首字母都替换成大写*/
String S="let there be light";
/*char[] c=S.toCharArray();
S.charAt(0);
for(int i=0;i<c.length;i++){
if(c[i]==(char)32){ //当i为空格时，后一个字符设为大写
char A=S.charAt(i+1);
c[i+1]=Character.toUpperCase(A);
}
}
c[0]=Character.toUpperCase(S.charAt(0)); //将第一个字符设为大写
S=new String(c);
System.out.println(S);*/
//方法二
String[] s1=S.split(" "); //用空格进行分隔字符串，变成字符串数组
for(int i=0;i<s1.length;i++){
String s2=s1[i].substring(0,1).toUpperCase(); //将字符串数组的子字符串的第一个进行转大写
String s3=s1[i].substring(1); //子字符串下标1开始后面的字符
s3=s2+s3; //拼接回去
System.out.print(s3+" "); //打印
}
System.out.println();
}
public void count_same_p(){
/*英文绕口令，统计这段绕口令中有多少个以p开头的单词*/
int count=0;
String s1="peter piper picked a peck of pickled peppers";
String[] s2=s1.split(" "); //字符串中的空格来将s1分成了长度为8的字符串数组
for(int i=0;i<s2.length;i++){
String s3=s2[i].substring(0,1); //截取子字符串的首位
if(s3.equals("p")){ //比较字符串是否相等
count++;
}
}
System.out.println("以p开头的单词共有"+count+"个");
}
public void Low_toUpper(){
/*把lengendary改成间隔大小写模式，即LeNgEnDaRy*/
String s="lengendary";
char[] s1=s.toCharArray();
for(int i=0;i<s1.length;i+=2){
s1[i]=Character.toUpperCase(s1[i]);
}
String s2=String.valueOf(s1); //将字符数组转换成字符串
System.out.println("转换之后的字符串为："+s2);
}
public void replace_last() {
//将最后一个two单词首字母大写
String s = "Nature has given us that two ears, two eyes, and but one tongue, to the end that we should hear and see more than we speak";
System.out.println(s);
/*int a=s.lastIndexOf("two"); //找出字符串中最后一个出现two的下标
char[] s1=s.toCharArray(); //转换成字符数组
s1[a]=Character.toUpperCase(s1[a]); //将这个下标对应的字符转换成大写
s=new String(s1); //字符数组转换成字符串
System.out.println(s);*/
//方法二
String[] s1 = s.split(" "); //使用空格分隔字符串为字符数组
for (int i = s1.length - 1; i > 0; i--) { //从后往前，降低时间复杂度
if (s1[i].equals("two")) {
String s2 = s1[i].substring(0,1).toUpperCase(); //将首字符转换为大写
String s3 = s1[i].substring(1); //子字符串下标1开始后面的字符
s1[i] = s2 + s3;
break;
}
}
for (String s4 : s1) {
System.out.print(s4 + " "); //打印子字符串数组
}
}
public static void main(String[] args){
ControlString c1=new ControlString();
c1.First_toUpper();
c1.count_same_p();
c1.Low_toUpper();
c1.replace_last();
}
}
