C++ prime plus-7-編程練習
1,
#include <iostream>// 函数声明
double harmonicMean(double x, double y);int main() {double x, y, result;while (true) {std::cout << "请输入两个数(其中一个为0时结束): ";std::cin >> x >> y;// 检查是否输入了0if (x == 0 || y == 0) {break;}// 计算调和平均数result = harmonicMean(x, y);// 报告结果std::cout << "调和平均数是: " << result << std::endl;}std::cout << "程序结束。" << std::endl;return 0;
}// 函数定义
double harmonicMean(double x, double y) {if (x == 0 || y == 0) {return 0; // 如果其中一个数为0,则调和平均数没有意义}return 2.0 * x * y / (x + y);
}
2,
#include <iostream>
#include <vector>// 声明数组函数
void inputScores(std::vector<int>& scores);
void displayScores(const std::vector<int>& scores);
double calculateAverage(const std::vector<int>& scores);int main() {std::vector<int> scores;inputScores(scores);displayScores(scores);double average = calculateAverage(scores);std::cout << "平均成绩是: " << average << std::endl;return 0;
}// 实现输入函数
void inputScores(std::vector<int>& scores) {int score;std::cout << "请输入高尔夫成绩(输入非数字结束): ";while (std::cin >> score && scores.size() < 10) {scores.push_back(score);std::cout << "继续输入高尔夫成绩(输入非数字结束): ";}std::cin.clear(); // 清除错误状态std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // 忽略剩余输入
}// 实现显示函数
void displayScores(const std::vector<int>& scores) {std::cout << "输入的成绩为: ";for (int i = 0; i < scores.size(); ++i) {std::cout << scores[i] << " ";}std::cout << std::endl;
}// 实现计算平均成绩函数
double calculateAverage(const std::vector<int>& scores) {if (scores.empty()) {return 0.0;}int sum = 0;for (int score : scores) {sum += score;}return static_cast<double>(sum) / scores.size();
}
3,
#include <iostream>
#include <cstring> // 用于处理字符串struct box {char maker[40];float height;float width;float length;float volume;
};// 函数声明
void displayBox(const box& b);
void calculateVolume(box& b);int main() {box myBox;// 获取用户输入std::cout << "请输入制造商名称: ";std::cin.getline(myBox.maker, 40);std::cout << "请输入高度: ";std::cin >> myBox.height;std::cout << "请输入宽度: ";std::cin >> myBox.width;std::cout << "请输入长度: ";std::cin >> myBox.length;// 计算体积calculateVolume(myBox);// 显示盒子信息displayBox(myBox);return 0;
}// 按值传递box结构,并显示每个成员的值
void displayBox(const box& b) {std::cout << "制造商: " << b.maker << std::endl;std::cout << "高度: " << b.height << std::endl;std::cout << "宽度: " << b.width << std::endl;std::cout << "长度: " << b.length << std::endl;std::cout << "体积: " << b.volume << std::endl;
}// 传递box结构的地址,并将volume成员设置为其他三维长度的乘积
void calculateVolume(box& b) {b.volume = b.height * b.width * b.length;
}
4,
#include <iostream>
#include <cmath> // 用于log和pow函数// 计算阶乘的函数
double factorial(int n) {double result = 1;for (int i = 2; i <= n; ++i) {result *= i;}return result;
}// 计算组合数的函数
double combination(int n, int k) {return factorial(n) / (factorial(k) * factorial(n - k));
}// 计算几率的对数的函数
double logCombination(int n, int k) {return lgamma(n + 1) - (lgamma(k + 1) + lgamma(n - k + 1));
}int main() {int fieldNumbers = 47; // 域号码的数量int chosenNumbers = 5; // 选择的号码数量int specialNumbers = 27; // 特选号码的数量// 计算中头奖的几率的对数double logOdds = logCombination(fieldNumbers, chosenNumbers) + logCombination(specialNumbers, 1);// 输出几率的对数std::cout << "中头奖的几率的对数是: " << logOdds << std::endl;// 如果需要,可以计算几率的实际值double odds = exp(logOdds);std::cout << "中头奖的几率是: " << odds << std::endl;return 0;
}
5,
#include <iostream>// 递归函数声明
unsigned long long factorial(int n);int main() {int number;std::cout << "请输入一个整数(输入-1结束): ";while (std::cin >> number && number != -1) {unsigned long long result = factorial(number);std::cout << number << "! = " << result << std::endl;std::cout << "请输入一个整数(输入-1结束): ";}std::cout << "程序结束。" << std::endl;return 0;
}// 递归函数定义
unsigned long long factorial(int n) {if (n <= 1) { // 基本情况return 1;} else { // 递归情况return n * factorial(n - 1);}
}
6,
#include <iostream>
#include <limits> // 用于std::numeric_limits// 函数声明
int fill_array(double arr[], int size);
void show_array(const double arr[], int size);
void reverse_array(double arr[], int size);int main() {const int size = 10; // 定义数组大小double array[size];// 使用fill_array函数填充数组int count = fill_array(array, size);std::cout << "填充了 " << count << " 个数字。" << std::endl;// 显示数组内容std::cout << "原始数组:" << std::endl;show_array(array, count);// 反转数组reverse_array(array, count);// 显示反转后的数组内容std::cout << "反转后的数组:" << std::endl;show_array(array, count);// 再次反转数组中除第一个和最后一个元素之外的所有元素reverse_array(array + 1, count - 2);// 显示最终数组内容std::cout << "最终数组:" << std::endl;show_array(array, count);return 0;
}// fill_array函数定义
int fill_array(double arr[], int size) {int count = 0;double value;std::cout << "请输入 " << size << " 个double值 (输入非数字结束):" << std::endl;while (count < size && std::cin >> value) {arr[count++] = value;}std::cin.clear(); // 清除错误状态std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // 忽略剩余输入return count;
}// show_array函数定义
void show_array(const double arr[], int size) {for (int i = 0; i < size; ++i) {std::cout << arr[i] << " ";}std::cout << std::endl;
}// reverse_array函数定义
void reverse_array(double arr[], int size) {for (int i = 0; i < size / 2; ++i) {double temp = arr[i];arr[i] = arr[size - i - 1];arr[size - i - 1] = temp;}
}
7,
#include <iostream>
#include <limits> // 用于std::numeric_limits// 函数声明
double* fill_array(double* start, double* end);
void show_array(const double* start, const double* end);
void reverse_array(double* start, double* end);int main() {const int size = 10; // 定义数组大小double array[size];// 使用fill_array函数填充数组double* fill_end = fill_array(array, array + size);std::cout << "数组填充结束位置:" << fill_end << std::endl;// 显示数组内容std::cout << "原始数组:" << std::endl;show_array(array, fill_end);// 反转数组reverse_array(array, fill_end);// 显示反转后的数组内容std::cout << "反转后的数组:" << std::endl;show_array(array, fill_end);// 再次反转数组中除第一个和最后一个元素之外的所有元素reverse_array(array + 1, fill_end - 1);// 显示最终数组内容std::cout << "最终数组:" << std::endl;show_array(array, fill_end);return 0;
}// fill_array函数定义
double* fill_array(double* start, double* end) {double value;std::cout << "请输入double值 (输入非数字结束):" << std::endl;while (start < end && std::cin >> value) {*start++ = value;}std::cin.clear(); // 清除错误状态std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // 忽略剩余输入return start; // 返回最后被填充的位置
}// show_array函数定义
void show_array(const double* start, const double* end) {while (start < end) {std::cout << *start++ << " ";}std::cout << std::endl;
}// reverse_array函数定义
void reverse_array(double* start, double* end) {while (start < end) {double temp = *start;*start = *end;*end = temp;start++;end--;}
}
8,
#include <iostream>
#include <string>const int NUM_QUARTERS = 4; // 定义季度数量int main() {const char* quarters[NUM_QUARTERS] = {"Q1", "Q2", "Q3", "Q4"};double expenses[NUM_QUARTERS] = {0};// 输入每个季度的开支for (int i = 0; i < NUM_QUARTERS; ++i) {std::cout << "请输入 " << quarters[i] << " 的开支: ";std::cin >> expenses[i];}// 显示每个季度的开支std::cout << "\n季度开支:" << std::endl;for (int i = 0; i < NUM_QUARTERS; ++i) {std::cout << quarters[i] << ": " << expenses[i] << std::endl;}return 0;
}
9,
#include <iostream>
#include <string>
using namespace std;const int SLEN = 30;struct student {char fullname[SLEN];char hobby[SLEN];int age;
};// 获取学生信息的函数
int getinfo(student *arr, int n) {int count = 0;string line;while (count < n) {cout << "请输入学生姓名: ";getline(cin, line);if (line.empty()) {break; // 如果输入的是空行,则终止输入}strncpy(arr[count].fullname, line.c_str(), SLEN - 1);arr[count].fullname[SLEN - 1] = '\0'; // 确保字符串以空字符结尾cout << "请输入学生爱好: ";getline(cin, line);strncpy(arr[count].hobby, line.c_str(), SLEN - 1);arr[count].hobby[SLEN - 1] = '\0';cout << "请输入学生年龄: ";cin >> arr[count].age;cin.ignore(numeric_limits<streamsize>::max(), '\n'); // 忽略换行符count++;}return count; // 返回填充的数组元素数量
}// 显示学生信息的函数
void display(const student *s) {cout << "姓名: " << s->fullname << endl;cout << "爱好: " << s->hobby << endl;cout << "年龄: " << s->age << endl;
}int main() {const int MAX_STUDENTS = 5;student students[MAX_STUDENTS];int numStudents = getinfo(students, MAX_STUDENTS);cout << "\n学生信息:" << endl;for (int i = 0; i < numStudents; i++) {display(&students[i]);cout << endl;}return 0;
}
10,
#include <iostream>// 函数声明
double add(double x, double y);
double multiply(double x, double y);
double calculate(double x, double y, double (*pf)(double, double));int main() {double x, y, result;double (*pf[3])(double, double) = {add, multiply}; // 函数指针数组while (true) {std::cout << "请输入两个数字(输入非数字结束): ";std::cin >> x >> y;if (!std::cin) {std::cin.clear(); // 清除错误状态std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // 忽略剩余输入break;}// 使用 calculate 调用不同的函数std::cout << "加法结果: " << calculate(x, y, add) << std::endl;std::cout << "乘法结果: " << calculate(x, y, multiply) << std::endl;std::cout << "\n继续输入两个数字,或输入非数字结束程序。\n";}std::cout << "程序结束。" << std::endl;return 0;
}// add 函数定义
double add(double x, double y) {return x + y;
}// multiply 函数定义
double multiply(double x, double y) {return x * y;
}// calculate 函数定义
double calculate(double x, double y, double (*pf)(double, double)) {return pf(x, y);
}