20155336 第十二周课堂总结 20155336虎光元

20155336 第十二周课堂总结 20155336虎光元

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 class Score2
{
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,20155339);
for(int score : scores)
{
System.out.printf("%9d",score);
}
}
}

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。

参考代码

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

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]);
}
}
}
}

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