106BLec4作业有感

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作业1

We wrote various tests for the extractAlpha() function in class today. Add to that code a separate STUDENT_TEST that contains a suite of test cases for the passwordChecksOut() function. What sorts of things would you test to ensure you have robust testing coverage for that function?

我们今天在课堂上为 extractAlpha（） 函数编写了各种测试。在该代码中添加一个单独的 STUDENT_TEST，其中包含一套 passwordChecksOut（） 函数的测试用例。您将测试哪些内容来确保该函数具有强大的测试覆盖率？

主要是为了给 passwordChecksOut（） 函数编写测试用例没有难度

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#include <iostream>
#include "console.h"
#include "SimpleTest.h"
#include "strlib.h"
using namespace std;

string extractAlpha(string s)
{
    string result;

    for (int i = 0; i < s.length(); i++)
    {
        if (isalpha(s[i]))
        {
            result += s[i];
        }
    }
    return result;
}

bool passwordChecksOut(string username, string password)
{
    string alphaPortion = extractAlpha(password);
    return !stringContains(toLowerCase(alphaPortion), toLowerCase(username));
}

STUDENT_TEST("various tests of extractAlpha() function")
{
    EXPECT_EQUAL(extractAlpha("sean"), "sean");
    EXPECT_EQUAL(extractAlpha("sean11"), "sean");
    EXPECT_EQUAL(extractAlpha("1sean"), "sean");
    EXPECT_EQUAL(extractAlpha("s1ean"), "sean");
    EXPECT_EQUAL(extractAlpha("s1e1a1n"), "sean");
    EXPECT_EQUAL(extractAlpha("s9e$a***&n"), "sean");
    EXPECT_EQUAL(extractAlpha(""), "");
    EXPECT_EQUAL(extractAlpha("9$&"), "");
}

STUDENT_TEST("这是我的测试, 关于函数 passwordChecksOut()")
{
    EXPECT_EQUAL(passwordChecksOut("dk","d9327309k**%dd"), false);
    EXPECT_EQUAL(passwordChecksOut("dk","kdbusa*7^//"),true);
}

int main_test()
{
    runSimpleTests(ALL_TESTS);

    string username = "Sean";
    string password = "s1e1a1n1'1s1p1a1s1s1w1o1r1d";

    if (passwordChecksOut(username, password))
    {
        cout << "Hooray!" << endl;
    }
    else
    {
        cout << "Oh no! Bad password." << endl;
    }

    return 0;
}

作业2

简单情形

Write a function that takes a vector of integers as its only argument and prints it in the following format:

编写一个函数，该函数将整数向量作为其唯一参数，并按以下格式打印：

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+----+----+----+----+----+----+
| 43 | 19 | 12 | 95 | 83 | 13 |
+----+----+----+----+----+----+
  0    1    2    3    4    5

The function signature is: 函数签名为：

1

printVector(Vector<int>& v)

To simplify the problem, you may assume all the integers in the vector have exactly two digits. 为了简化问题，您可以假设向量中的所有整数恰好有两位数字。

这个问题也是简单的, 因为假设了二位整数所以没有任意整数的困难(包括负数, 位数不同等).

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#include <iostream>
#include "console.h"
#include "SimpleTest.h"
#include "vector.h"
#include "string.h"
using namespace std;

void printVector(Vector<int>& v)
{
    string s1, s2, s3;
    int count = 0;
    for (int i : v)
    {
        s1 += "+----";
        s2 += "| " + to_string(i) + " ";
        s3 += "  " + to_string(count) + "  ";
        ++count;
    }
    s1 += "+";
    s2 += "|";
    cout << s1 << "\n"
         << s2 << "\n"
         << s1 << "\n"
         << s3 << endl;
}


int main_printVector()
{
    Vector<int> v1 = {43, 19, 12, 95, 83, 13};
    printVector(v1);
    // cout << "+----+----+----+----+----+----+\n| 43 | 19 | 12 | 95 | 83 | 13 |\n+----+----+----+----+----+----+\n  0    1    2    3    4    5";
    return 0;
}

改进

Additional challenge (this is fairly advanced; don’t worry too much about this one if you don’t have time): 额外的挑战（这是相当高级的，如果你没有时间，不要太担心这个）：

  • How could you ensure when printing the contents of a vector that the largest box has exactly enough space for the largest integer in the vector to be surrounded by one space on either side, and all other boxes have the same amount of space, with each integer being centered within its cell to the extend possible? For example: 在打印向量的内容时，如何确保最大的框有足够的空间让向量中最大的整数在两侧被一个空格包围，并且所有其他框具有相同的空间量，每个整数在其单元格内居中，尽可能地扩大？ 例如：
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+------+------+------+------+------+------+
|  43  |  1   |  9   | 129  | 5821 |  3   |
+------+------+------+------+------+------+
   0      1      2      3      4      5

这里位数不同的问题应该是普遍意识到的问题, 但是还有一个问题在于我们事实上是可以考虑负数的情形的但是这样需要考虑一些额外的情况.

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+-------+-------+-------+-------+-------+-------+-------+
|  43   |   1   |   9   |  129  | 5821  |   3   | -5633 |
+-------+-------+-------+-------+-------+-------+-------+
    0       1       2       3       4       5       6

如图所示存在问题: 计算整数位数时, 负数需要计算-号也会占用一个位置.

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#include <iostream>
#include "console.h"
#include "SimpleTest.h"
#include "string.h"
#include "vector.h"
using namespace std;

int widthOfNum(int num){
    if (num == 0) return 1; // 0是1位数

    int count = 0;
    // 处理负数：转换为正数
    if (num < 0) {
        num = -num;
        ++count;
    }

    while (num > 0) {
        count++;
        num /= 10;
    }
    return count;
}

int maxWidthOfVector(Vector<int> &v){
    int numVec = v.size();
    int maxNum = widthOfNum(v[0]);
    for(int i= 1;i<numVec;i++){
        if(widthOfNum(v[i]) > maxNum)
        {maxNum = widthOfNum(v[i]);}
    }
    return maxNum;
}



void printVectorAdvanced(Vector<int> &v)
{
    //runSimpleTests(SELECTED_TESTS);
    int maxVecWidth = maxWidthOfVector(v)+2;
    string s1,s2,s3;
    int count = 0;
    for(int i:v)
    {
        int iWidth = widthOfNum(i);
        s1 += string("+") + string(maxVecWidth,'-');
        int whiteSpace1 = (maxVecWidth-iWidth)/2;
        int whiteSpace2 = maxVecWidth - whiteSpace1-iWidth;
        s2 += string("|") + string(whiteSpace1,' ') + to_string(i) + string(whiteSpace2,' ');
        int whiteSpace3 = (maxVecWidth+1)/2;
        s3 += string(whiteSpace3,' ') + to_string(count) + string(maxVecWidth/2,' ');
        count++;
    }
    s1 += string("+");
    s2 += string("|");
    cout << s1 << "\n" << s2 << "\n" << s1 << "\n" << s3 << endl;
}

STUDENT_TEST("测试maxWidthOfVector函数")
{
    Vector<int> v1 = {43,1,9,129,5821,3};
    Vector<int> v2 = {43,1,9,129,582,3,-256};
    EXPECT_EQUAL(maxWidthOfVector(v1), 4);
    EXPECT_EQUAL(maxWidthOfVector(v2), 7);
}


STUDENT_TEST("测试函数widthOfNum"){
    EXPECT_EQUAL(widthOfNum(1890),4);
    EXPECT_EQUAL(widthOfNum(0),1);
    EXPECT_EQUAL(widthOfNum(-1),2);
}

int main()
{
    //runSimpleTests(SELECTED_TESTS);
    Vector<int> v1 = {43,1,9,129,5821,3};
    Vector<int> v2 = {43,1,9,129,5821,3,-5633};
    printVectorAdvanced(v2);
    return 0;
}

可能的改进

  1. 可能可以使用一些更好的方法来拼接字符串或者是直接打印.

作业3

In the previous problem, why would we pass the vector by reference if we have no intention of modifying it in the printVector() function?

在上一个问题中，如果我们无意在 printVector（） 函数中修改向量，为什么还要通过引用传递向量？

个人感觉还是直接传递变量副本太占据存储空间.

Tips: 需要注意所有程序中的 main() 函数都添加了 _filename 使得能够在同一个空白项目中编译成功, 需要用的时候去掉后缀同时保证项目中没有其他 main() 函数即可