20175204 张湲祯 2018-2019-2《Java程序设计》

Arrays和String单元测试

一.类的作用

1.- String类

charAt

String的charAt的作用是将字符串中第i个位置上的字符（从0开始计数）赋值给n，其用法为n=string.charAt(i)

split

String的split的作用是将字符串拆分成为几个字符串，其用法为(将字符串string以：为界限进行拆分，将拆分的几个字符串赋值给字符串数组string1)string1=string.split(":")

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2.- Arrays类

sort

Arrays的sort的作用是将数组中的元素从小到大排序，其用法为(对arr数组进行排序)Arrays.sort(arr);

binarySearch

Arrays的binarySearch是寻找数组中某个元素所处的位置，其用法为(在arr中寻找数字1，将数字1的位置赋值给n，从0开始计数)n=Arrays.binarySearch(arr,1);

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二.相关代码

测试代码

import junit.framework.TestCase;
import org.junit.Test;
import java.lang.*;
import java.util.Arrays;
public class ComplexTest extends TestCase {
    String str = "zyz is xinzhou huge";
    String str2 = "zyz:is:xin:zhou:hu:ge";
    String[] str3 = new String[]{  "1", "7", "5", "2", "0", "4"};
    double str4[] = {2.0, 1.7, 5.2, 0.4, 66.6};
    @Test     public void testcharAt() throws Exception {
        assertEquals('z', Complex.getcharAt(str,0));
        assertEquals('y', Complex.getcharAt(str,1));
        assertEquals('z', Complex.getcharAt(str,2));
        assertEquals('h', Complex.getcharAt(str,15));
        assertEquals('g', Complex.getcharAt(str,17));
    }
    @Test     public void testsplit() throws Exception {
        assertEquals("zyz", Complex.getsplit(str2)[0]);
        assertEquals("hu", Complex.getsplit(str2)[4]);
        assertEquals("ge", Complex.getsplit(str2)[5]);
    }
    @Test     public void testgetsort() throws Exception {
        //ArraysTest(str3);
        assertEquals("5", Complex.getsort(str3)[4]);
        assertEquals("2", Complex.getsort(str3)[2]);
        assertEquals("0", Complex.getsort(str3)[0]);
        assertEquals("4", Complex.getsort(str3)[3]);
    }
    @Test
    public void testgetbinarySearch() throws Exception {
        //ArraysTest2(str4);
        assertEquals(2, Arrays.binarySearch(Complex.getbinarySearch(str4), 2.0));
        assertEquals(0, Arrays.binarySearch(Complex.getbinarySearch(str4), 0.4));
        assertEquals(4, Arrays.binarySearch(Complex.getbinarySearch(str4), 66.6));
    }
    }

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import java.util.Arrays;
public class Complex{
    //测试charAt
    public static char charAt(String str, int i) {
        return str.charAt(i);
    }
    public static char getcharAt(String str, int i) {
        return charAt(str, i);
    }
    //测试split
    public static String[] split(String str) {
        String[] strsort = str.split(":");
        return strsort;
    }
    public static String[] getsplit(String str) {
        return split(str);
    }
    //测试sort
    public static String[] sort(String[] str3) {
        Arrays.sort(str3);
        return str3;
    }
    public static String[] getsort(String[] str3) {
        return sort(str3);
    }
    //测试binarySearch
    public static double[] binarySearch(double[] str4) {
        Arrays.sort(str4);
        return str4;
    }
    public static double[] getbinarySearch(double[] str4) {
        return binarySearch(str4);
    }

}

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运行截图