OOP - 实验一

任务1：代码：

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

template<typename T>
void output(const T &c);
void test1();
void test2();
void test3();
int main() {
    std::cout << "测试1: \n";
    test1();
    std::cout << "\n测试2: \n";
    test2();
    std::cout << "\n测试3: \n";
    test3();
}

template <typename T>
void output(const T &c) {
    for(auto &i : c)
        std::cout << i << ' ';
    std::cout << '\n';
}

void test1() {
    using namespace std;
    string s0{"0123456789"};
    cout << "s0 = " << s0 << endl;
    string s1(s0);
    reverse(s1.begin(), s1.end()); 
    cout << "s1 = " << s1 << endl;
    string s2(s0.size(), ' ');
    reverse_copy(s0.begin(), s0.end(), s2.begin()); 
    cout << "s2 = " << s2 << endl;
}

void test2() {
    using namespace std;
    vector<int> v0{2, 0, 4, 9};
    cout << "v0: "; output(v0);
    vector<int> v1{v0};
    reverse(v1.begin(), v1.end());
    cout << "v1: "; output(v1);
    vector<int> v2{v0};
    reverse_copy(v0.begin(), v0.end(), v2.begin());
    cout << "v2: "; output(v2);
}

void test3() {
    using namespace std;
    vector<int> v0{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    cout << "v0: "; output(v0);
    vector<int> v1{v0};
    rotate(v1.begin(), v1.begin()+1, v1.end()); 
    cout << "v1: "; output(v1);
    vector<int> v2{v0}; 
    rotate(v2.begin(), v2.begin()+2, v2.end()); 
    cout << "v2: "; output(v2);
    vector<int> v3{v0};
    rotate(v3.begin(), v3.end()-1, v3.end()); 
    cout << "v3: "; output(v3);
    vector<int> v4{v0};
    rotate(v4.begin(), v4.end()-2, v4.end()); 
    cout << "v4: "; output(v4);
}

运行结果：

 问题1：reverse的反转操作实在当前数组内进行，会直接改变当前数组的顺序，而reverse_copy是将反转后的数组拷贝到一个新的容器内，不会改变当前数组。

问题2：rotate（参数1，参数2，参数3）函数是一个循环位移函数，参数1和3分别代表要循环的部分的起点和终点，参数二代表循环位移后位于第一个位置的元素。

 

任务2：代码：

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <iomanip>
#include <cstdlib>
#include <ctime>

template<typename T>
void output(const T &c);

int generate_random_number();
void test1();
void test2();

int main() {
    std::srand(std::time(0));  
    std::cout << "测试1: \n";
    test1();
    std::cout << "测试2: \n";
    test2();
}

template<typename T>
void output(const T &c) {
    for (auto i : c)
        std::cout << i << ' ';
    std::cout << '\n';
}

int generate_random_number() {
    return std::rand() % 101;
}

void test1() {
    using namespace std;
    vector<int> v0(10);  
    generate(v0.begin(), v0.end(), generate_random_number); 
    cout << "v0: "; output(v0);

    vector<int> v1(v0);
    sort(v1.begin(), v1.end()); 
    cout << "v1: "; output(v1);

    vector<int> v2(v0);
    sort(v2.begin()+1, v2.end()-1); 
    cout << "v2: "; output(v2);
}

void test2() {
    using namespace std;
    vector<int> v0(10);
    generate(v0.begin(), v0.end(), generate_random_number);
    cout << "v0: "; output(v0);

    auto max_it = max_element(v0.begin(), v0.end());
    auto min_it = min_element(v0.begin(), v0.end());
    cout << "最小值: " << *min_it << endl;
    cout << "最大值: " << *max_it << endl;

    auto ans = minmax_element(v0.begin(), v0.end());
    cout << "最小值: " << *ans.first << endl;
    cout << "最大值: " << *ans.second << endl;

    double avg1 = accumulate(v0.begin(), v0.end(), 0.0) / v0.size();
    cout << "均值: " << fixed << setprecision(2) << avg1 << endl;

    sort(v0.begin(), v0.end());
    double avg2 = accumulate(v0.begin() + 1, v0.end() - 1, 0.0) / (v0.size() - 2);
    cout << "去掉最大值、最小值之后，均值: " << avg2 << endl;
}

 问题1：通过第三参数来给第一参数和第二参数中间的位置填充数据/元素

问题2：只需要遍历一次容器内的数据元素，节省了时间和空间成本

问题3：效果相同

 

任务3：代码：

#include <iostream>
#include <string>
#include <algorithm>
#include <cctype>

unsigned char func(unsigned char c);
void test1();
void test2();

int main() {
    std::cout << "测试1：字符串大小写转换\n";
    test1();
    std::cout << "测试2：字符替换\n";
    test2();
}

unsigned char func(unsigned char c) {
    if (c == '1')
        return 'a';
    if (c == '2')
        return 'A';
    if (std::isalpha(c))
        return static_cast<unsigned char>(c + 1);
    return c;
}

void test1() {
    std::string s = "Hello World 2048!";
    std::cout << "s = " << s << "\n";
    std::string s1;
    for (char c : s)
        s1 += std::tolower(c);
    std::cout << "s1 = " << s1 << "\n";
    std::string s2;
    for (char c : s)
        s2 += std::toupper(c);
    std::cout << "s2 = " << s2 << "\n";
}

void test2() {
    std::string s1 = "I love C++!";
    std::cout << "s1 = " << s1 << "\n";
    std::string s2(s1.size(), '*');
    std::transform(s1.begin(), s1.end(), s2.begin(), func);
    std::cout << "s2 = " << s2 << "\n";
}

 问题1：把字符 1 转换为a，把字符 2 转换为A，把字母字符转换为其在字母表中后一个位置的字母。

问题2：将指定内容的大写字母全部转换为小写；将指定内容的小写字母全部转换为大写。

问题3：1：指定区域的起始位置，2：指定区域的结束位置，3：生成的数据开始存储的位置，4：数据转化/处理规则

 

任务4：代码：

#include <iostream>
#include <string>
#include <algorithm>

bool is_palindrome(const std::string &s);
bool is_palindrome_ignore_case(const std::string &s);

int main() {
    using namespace std;
    string s;

    // 多组输入，直到按下Ctrl+Z结束测试
    while(cin >> s) {
        cout << boolalpha
             << "区分大小写: " << is_palindrome(s) << "\n"
             << "不区分大小写: " << is_palindrome_ignore_case(s) << "\n\n";
    }
}

bool is_palindrome(const std::string &s){
    int left=0 ,right=s.size()-1 ;
    while(left<right){
        if(s[left]!=s[right]){
           return false ;
        }
        left++ ;
        right-- ;
    }
    return true ;
}

bool is_palindrome_ignore_case(const std::string &s){
    std::string s0 ;
    
    int left=0 ,right=s.size()-1 ;
    
    for(char c : s){
        s0 += tolower(c) ;
    }
    
    while(left<right){
        if(s0[left]!=s0[right]){
           return false ;
        }
        left++ ;
        right-- ;
    }
    return true ;
}

 思考：

 

任务5：代码：

#include <iostream>
#include <string>
#include <algorithm>

std::string dec2n(int x, int n = 2);

int main() {
    int x;
    while(std::cin >> x) {
        std::cout << "十进制: " << x << '\n'
                  << "二进制: " << dec2n(x) << '\n'
                  << "八进制: " << dec2n(x, 8) << '\n'
                  << "十二进制: " << dec2n(x, 12) << '\n'
                  << "十六进制: " << dec2n(x, 16) << '\n'
                  << "三十二进制: " << dec2n(x, 32) << "\n\n";
    }
}

std::string dec2n(int x, int n){
    std::string result ;
    char str ;
    if(x == 0){
        return "0" ;
    }
    
    while(x>0){
        int remainder = x % n ;
        if( remainder < 10 ){
            str = '0' + remainder ;
        }
        else{
            str = 'A' + remainder - 10 ;
        }
        
        result.insert(0 , 1, str) ;
        
        x = x/n ;
    }
    return result ;
}

 

 

任务6：代码：

#include<iostream>
#include<string>
#include<cctype>
#include<iomanip>
#include<algorithm> 
using namespace std ;

int main(){
    string str = " a b c d e f g h i j k l m n o p q r s t u v w x y z" ;
    
    cout << "  " << str << endl ;
    
    for (char &c : str) {
        if (c != ' ') {
            c = toupper(c);
        }
    }
    
    for(int i = 1 ; i <= 26 ; i++){
        rotate(str.begin(), str.begin() + 2, str.end()) ; 
        cout << setw(2) << i << str << endl ;
    }
    
    return 0 ;
}

 

 

任务7：代码：

#include<iostream>
#include<cstdlib>
#include<ctime>
#include<iomanip>
using namespace std ;

int main() {
    srand(static_cast<unsigned int>(time(0))) ;

    int correctCount = 0 ;

    for (int i = 0; i < 10; i++) {
        int num1 = rand() % 10 + 1 ;
        int num2 = rand() % 10 + 1 ;
        int op = rand() % 4 ;
        int userAnswer, correctAnswer ;
        char operation ;

        if (op == 1) {
            if (num1 < num2) {
                swap(num1, num2) ;
            }
            operation = '-' ;
            correctAnswer = num1 - num2 ;
        } 
        
        else if (op == 3) {
            do {
                num1 = rand() % 10 + 1 ;
            } while (num1 % num2 != 0) ;
            operation = '/' ;
            correctAnswer = num1 / num2 ;
        } 

        else if (op == 0) {
            operation = '+' ;
            correctAnswer = num1 + num2 ;
        } 

        else {
            operation = '*' ;
            correctAnswer = num1 * num2 ;
        }

        cout << num1 << " " << operation << " " << num2 << " = " ;
        cin >> userAnswer ;

        if (userAnswer == correctAnswer) {
            correctCount++ ;
        }
    }

    double accuracy = static_cast<double>(correctCount) * 100 / 10 ;
    cout << "正确率: " << fixed << setprecision(1) << accuracy << "%" << endl ;

    return 0 ;
}