实验1 现代c++编程初体验
任务1：
task1.cpp
// 现代C++标准库、算法库体验
// 本例用到以下内容:
// 1. 字符串string, 动态数组容器类vector、迭代器
// 2. 算法库：反转元素次序、旋转元素
// 3. 函数模板、const引用作为形参
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
// 声明
// 模板函数声明
template<typename T>
void output(const T &c);
// 普通函数声明
void test1();
void test2();
void test3();
int main() {
cout << "测试1: \n";
test1();
cout << "\n测试2: \n";
test2();
cout << "\n测试3: \n";
test3();
}
// 函数实现
// 输出容器对象c中的元素
template <typename T>
void output(const T &c) {
for(auto &i: c)
cout << i << " ";
cout << endl;
}
// 测试1
// 组合使用算法库、迭代器、string反转字符串
void test1() {
string s0{"0123456789"};
cout << "s0 = " << s0 << endl;
string s1{s0};
reverse(s1.begin(), s1.end()); // 反转指定迭代器区间的元素
cout << "s1 = " << s1 << endl;
string s2{s0};
reverse_copy(s0.begin(), s0.end(), s2.begin()); // 将指定迭代区间的元素拷贝到指定迭代器开始的目标区间，并且在复制过程中反转次序
cout << "s2 = " << s2 << endl;
}
// 测试2
// 组合使用算法库、迭代器、vector反转动态数组对象vector内数据
void test2() {
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);
}
// 测试3
// 组合使用算法库、迭代器、vector实现元素旋转移位
void test3() {
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()); // 旋转指定迭代器区间[v1.begin(), v1.end())之间的数据项，旋转后从迭代器v1.begin()+1位置的数据项开始
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);
}
实验结果截图
任务2：
task2.cpp
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <numeric>
#include <iomanip>
using namespace std;
// 函数声明
// 模板函数声明
template<typename T>
void output(const T &c);
// 普通函数声明
int rand_int_100();
void test1();
void test2();
int main() {
cout << "测试1: \n";
test1();
cout << "\n测试2: \n";
test2();
}
// 函数实现
// 输出容器对象c中的元素
template <typename T>
void output(const T &c) {
for(auto &i: c)
cout << i << " ";
cout << endl;
}
// 返回[0, 100]区间内的一个随机整数
int rand_int_100() {
return rand() % 101;
}
// 测试1
// 对容器类对象指定迭代器区间进行赋值、排序
void test1() {
vector<int> v0(10); // 创建一个动态数组对象v0, 对象大小为10
generate(v0.begin(), v0.end(), rand_int_100); // 产生[0, 100]之间的随机整数赋值给指定迭代器区间[v0.begin(), v0.end())内的每个数据项
cout << "v0: ";
output(v0);
vector<int> v1{v0};
sort(v1.begin(), v1.end()); // 对指定迭代器区间[v1.begin(), v1.end())内数据项进行升序排序
cout << "v1: ";
output(v1);
vector<int> v2{v0};
sort(v2.begin()+1, v2.end()-1); // 对指定迭代器区间[v1.begin()+1, v1.end()-1)内数据项进行升序排序
cout << "v2: ";
output(v2);
}
// 测试2
// 对容器类对象指定迭代器区间进行赋值、计算最大值/最小值/均值
void test2() {
vector<int> v0(10);
generate(v0.begin(), v0.end(), rand_int_100);
cout << "v0: ";
output(v0);
auto iter1 = min_element(v0.begin(), v0.end());
cout << "最小值: " << *iter1 << endl;
auto iter2 = max_element(v0.begin(), v0.end());
cout << "最大值: " << *iter2 << 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)/v0.size();
cout << "均值: " << fixed << setprecision(2) << avg1 << endl;
cout << endl;
vector<int> v1{v0};
cout << "v0: ";
output(v0);
sort(v1.begin(), v1.end());
double avg2 = accumulate(v1.begin()+1, v1.end()-1, 0)/(v1.size()-2);
cout << "去掉最大值、最小值之后，均值: " << avg2 << endl;
}
实验结果截图
任务三:
task3.cpp
#include <iostream>
#include <string>
#include <algorithm>
bool is_palindrome(std::string s)
{
std::string reversed_s=s;
std::reverse(reversed_s.begin(),reversed_s.end());
if(s==reversed_s)
{
return true;
}
else
{
return false;
}
}
int main() {
using namespace std;
string s;
while(cin >> s)
cout << boolalpha << is_palindrome(s) << endl;
}
实验结果截图
任务四:
task4.cpp
#include <iostream>
#include <string>
#include <algorithm>
std::string dec2n(int x, int n = 2)
{
std::string result;
if(x==0)
result+='0';
while(x>0)
{
int remainder=x%n;
if(remainder<10)
{
result+=remainder+'0';
}
else
{
result+=remainder-10+'A';
}
x/=n;
}
std::reverse(result.begin(),result.end());
return result;
}
int main() {
using namespace std;
int x;
while(cin >> x) {
cout << "十进制: " << x << endl;
cout << "二进制: " << dec2n(x) << endl;
cout << "八进制: " << dec2n(x, 8) << endl;
cout << "十六进制: " << dec2n(x, 16) << endl << endl;
}
}
实验结果截图
实验五:
task5.cpp
#include <iostream>
#include <iomanip>
int main()
{
using namespace std;
char letters[26] = {'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<<" ";
for (int i=0; i < 26; i++)
{
cout << (char)(letters[i]+32)<<' ';
}
cout << endl;
for (int i = 1; i < 26; i++)
{
cout<<setw(2) << i <<' ';
for (int j = 0; j < 26; j++)
{
char currentLetter = letters[(i + j) % 26];
cout << currentLetter << ' ';
}
cout << endl;
}
cout<<setw(2)<<26<<' ';
for (int i=0; i < 26; i++)
{
cout <<letters[i]<<' ';
}
cout << endl;
return 0;
}
实验结果截图
实验六:
task6.cpp
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <ctime>
int main()
{
using namespace std;
srand(static_cast<unsigned int>(time(0)));
int correctCount = 0;
const int totalQuestions = 10;
for (int i = 0; i < totalQuestions; ++i)
{
int num1, num2;
char operation;
int answer;
int op = rand() % 4;
switch (op)
{
case 0:
num1 = rand() % 10 + 1;
num2 = rand() % 10 + 1;
operation = '+';
answer = num1 + num2;
break;
case 1:
num2 = rand() % 9 + 1;
num1 = num2 + (rand() % (11 - num2));
operation = '-';
answer = num1 - num2;
break;
case 2:
num1 = rand() % 10 + 1;
num2 = rand() % 10 + 1;
operation = '*';
answer = num1 * num2;
break;
case 3:
num2 = rand() % 9 + 1;
num1 = num2 * (rand() % (10 / num2) + 1);
operation = '/';
answer = num1 / num2;
break;
}
cout << num1 << " " << operation << " " << num2 << " = ";
int userAnswer;
cin >> userAnswer;
if (userAnswer == answer)
{
correctCount++;
}
}
double accuracy = (static_cast<double>(correctCount) / totalQuestions) * 100;
cout << fixed << setprecision(2);
cout << "你的正确率是：" << accuracy << "%" << endl;
return 0;
}
实验结果截图
