第四天----陣列和String
阿新 • • 發佈:2019-02-08
//氣泡排序法
int a[]={23,34,12,21};
int temp;
//Arrays.sort(a);
for (int f = 0; f < a.length; f++) {
for (int i = 0; i < a.length-f-1; i++) {
if(a[i]>a[i+1]){
temp=a[i+1];
a[i+1]=a[i];
a[i]=temp;
}
}
}
for (int i = 0; i < a.length; i++) {
System.out.println(a[i]);
}
//求平均數 float a; int[] array=new int [5]; int i = 0; float sum=0; for (; i < array.length; i++) { Scanner sca=new Scanner(System.in); array[i]=sca.nextInt(); sum+=array[i]; } a=sum/5; System.out.println(a);
//把字串中的大寫換成小寫,小寫換成大寫
String s="abc1ffFFJJKLOl";
String s1 = "";
for (int i = 0; i < s.length(); i++) {
char a=s.charAt(i);//得到字串中的字元
//判斷大小寫
if(a>='a'&&a<='z'){
a=(char) (a-32);
}else if (a>='A'&&a<='Z'){
a=(char)(a+32);
}
//把字元造型成字串
s1=s1.concat(""+a);
}
System.out.println(s1);
或
//將字串中的大寫變小寫,小寫變大寫
String s1 = new String ("AccHujR55");
//String s1 = "AccHujR55";
String s4 = "";
for (int j = 0; j < s1.length(); j++) {
char c = s1.charAt(j);
if (c>='a'&&c<='z'){
c = Character.toUpperCase(c);
}else if (c>='A'&&c<='Z'){
c = Character.toLowerCase(c);
}
s4=s4.concat(""+c);
}
System.out.println(s4);
import java.util.Scanner;
public class Buffer {
//一串整數,從左開始每個三個插入一個逗號
//String類的字串是不可以更改的,StringBuffer類的字串是可以更改的
public static void main(String[] args) {
// TODO Auto-generated method stub
StringBuffer buffer=new StringBuffer("123456789");
for (int i = 3; i < buffer.length(); i+=4) {
buffer.insert(i,',');
}
System.out.println(buffer);
}
}