20155318Java课堂实践20170510
修改教材P98 Score2.java
让执行结果数组填充是自己的学号：提交在IDEA或命令行中运行结查截图，加上学号水印，没学号的不给成绩
代码
public static void main(String[] args)
{
int[] scores = new int[10];
for(int score : scores)
{
System.out.printf("%2d",score);
}
System.out.println();
Arrays.fill(scores,20155318);
for(int score : scores)
{
System.out.printf("%9d",score);
}
}
截图
在IDEA中以TDD的方式对String类和Arrays类进行学习
测试相关方法的正常，错误和边界情况
String类
- charAt
- split
Arrays类
- sort
- binarySearch
代码
package exp2;
import org.junit.Test;
import junit.framework.TestCase;
import junit.framework.TestResult;
import java.util.Arrays;
public class MyUtil1Test extends TestCase {
String s1 = "abcde";
String s2 = "aaa:bbb:ccc";
String[] a1 = {"aaa","bbb","ccc"};
int [] c1 = {2,5,3,4};
char [] c2 = {'a','b','c','d'};
@org.junit.Test
public void testNormal() {
assertEquals("不及格", MyUtil1.percentage2fivegrade(55));
assertEquals("及格", MyUtil1.percentage2fivegrade(65));
assertEquals("中等", MyUtil1.percentage2fivegrade(75));
assertEquals("良好", MyUtil1.percentage2fivegrade(85));
assertEquals("优秀", MyUtil1.percentage2fivegrade(95));
}
@org.junit.Test
public void testException() {
//测试出错情况
assertEquals("错误", MyUtil1.percentage2fivegrade(-10));
assertEquals("错误", MyUtil1.percentage2fivegrade(105));
}
@org.junit.Test
public void testBoundary() {
//测试边界情况
assertEquals("不及格", MyUtil1.percentage2fivegrade(0));
assertEquals("及格", MyUtil1.percentage2fivegrade(60));
assertEquals("中等", MyUtil1.percentage2fivegrade(70));
assertEquals("良好", MyUtil1.percentage2fivegrade(80));
assertEquals("优秀", MyUtil1.percentage2fivegrade(90));
assertEquals("优秀", MyUtil1.percentage2fivegrade(100));
}
@Test
public void charAt() throws Exception {
assertEquals('a',s1.charAt(0));
assertEquals('e',s1.charAt(4));
}
@Test
public void split() throws Exception {
assertEquals(a1,s2.split(":"));
}
@Test
public void sort() throws Exception{
Arrays.sort(c1);
assertEquals(5,c1[3]);
}
@Test
public void binarySearch() throws Exception{
int c;
c = Arrays.binarySearch(c2,'c');
assertEquals(2,c);
}
}
截图
模拟实现Linux下Sort -t : -k 2的功能。
参考 Sort的实现。提交码云链接和代码运行截图。
代码（码云链接）
import java.util.*;
public class MySort1 {
public static void main(String [] args) {
String [] toSort = {"aaa:10:1:1",
"ccc:30:3:4",
"bbb:50:4:5",
"ddd:20:5:3",
"eee:40:2:20"};
System.out.println("Before sort:");
for (String str: toSort)
System.out.println(str);
Arrays.sort(toSort);
System.out.println("After sort:");
for( String str : toSort)
System.out.println(str);
}
}
代码
package exam20170510;
/**
* Created by Administrator on 2017/5/10.
*/
import java.util.*;
import java.lang.*;
public class Mysort {
public static void main(String[] args) {
String[] toSort = {"aaa:10:1:1",
"ccc:30:3:4",
"bbb:50:4:5",
"ddd:20:5:3",
"eee:40:2:20"};
int [] tmp = new int [toSort.length];
int val;
String [] s;
System.out.println("Before sort:");
for (String i : toSort) {
System.out.println(i);
}
for(int i = 0; i < toSort.length; i++) {
s = toSort[i].split(":");
tmp[i] = Integer.parseInt(s[3]);
}
Arrays.sort(tmp);
System.out.println("After sort:");
for(int i = 0; i < toSort.length; i++)
for(int j = 0; j < toSort.length; j++){
s = toSort[j].split(":");
val = Integer.parseInt(s[3]);
if(val == tmp[i]) {
System.out.println(toSort[j]);
}
}
}
}