C++中的常见I/O方式 - ToB企服应用市场:ToB评测及商务社交产业平台

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
using namespace std;
struct Student {
string name;
int age;
vector<int> grades;
void display() const {
cout << "Name: " << name << ", Age: " << age << ", Grades: ";
for (int grade : grades) {
cout << grade << " ";
}
cout << endl;
}
};
int main() {
vector<Student> students;
string input;
cout << "Enter student information (name age grades), type 'end' to stop:" << endl;
while (true) {
getline(cin, input);
if (input == "end") break;
istringstream iss(input);
Student student;
iss >> student.name >> student.age;
int grade;
while (iss >> grade) {
student.grades.push_back(grade);
}
students.push_back(student);
}
cout << "Entered students:" << endl;
for (const Student& student : students) {
student.display();
}
return 0;
}

复制代码

复制代码

#include <sstream>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
struct Product {
string name;
double price;
int quantity;
void display() const {
cout << "Name: " << name << ", Price: " << price << ", Quantity: " << quantity << endl;
}
};
int main() {
vector<Product> products = {
{"Apple", 999.99, 5},
{"HuaWei", 699.99, 10},
{"SanXing", 299.99, 7}
};
ostringstream oss;
for (const Product& prod : products) {
oss << prod.name << " " << prod.price << " " << prod.quantity << "\n";
}
string productData = oss.str();
cout << "Serialized products:\n" << productData;
vector<Product> parsedProducts;
istringstream iss(productData);
string name;
double price;
int quantity;
while (iss >> name >> price >> quantity) {
parsedProducts.push_back({name, price, quantity});
}
cout << "Parsed products:" << endl;
for (const Product& prod : parsedProducts) {
prod.display();
}
return 0;
}

复制代码

复制代码

#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <iostream>
#include <cstring>
using namespace std;
struct Data {
char text[50];
int number;
void display() const {
cout << "Text: " << text << ", Number: " << number << endl;
}
};
int main() {
int fd = open("mmapdata.dat", O_RDWR | O_CREAT, 0644);
if (fd == -1) {
cerr << "Error opening file" << endl;
return 1;
}
Data data = {"Memory-mapped file example", 42};
write(fd, &data, sizeof(Data));
size_t filesize = sizeof(Data);
Data *map = static_cast<Data*>(mmap(0, filesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
if (map == MAP_FAILED) {
cerr << "Error mapping file" << endl;
close(fd);
return 1;
}
// 修改映射区域内容
strcpy(map->text, "Updated text");
map->number = 99;
// 取消映射
munmap(map, filesize);
close(fd);
// 读取文件内容
fd = open("mmapdata.dat", O_RDONLY);
if (fd == -1) {
cerr << "Error opening file" << endl;
return 1;
}
Data readData;
read(fd, &readData, sizeof(Data));
close(fd);
cout << "Read data:" << endl;
readData.display();
return 0;
}

复制代码

#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <iostream>
#include <cstring>
using namespace std;
int main() {
int server_fd = socket(AF_INET, SOCK_STREAM, 0);
if (server_fd == -1) {
cerr << "Error creating socket" << endl;
return 1;
}
struct sockaddr_in server_addr;
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(9090);
server_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(server_fd, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
cerr << "Error binding socket" << endl;
close(server_fd);
return 1;
}
if (listen(server_fd, 5) == -1) {
cerr << "Error listening on socket" << endl;
close(server_fd);
return 1;
}
cout << "Server listening on port 9090..." << endl;
int client_fd = accept(server_fd, nullptr, nullptr);
if (client_fd == -1) {
cerr << "Error accepting connection" << endl;
close(server_fd);
return 1;
}
char buffer[256];
ssize_t bytesReceived = recv(client_fd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived == -1) {
cerr << "Error receiving data" << endl;
close(client_fd);
close(server_fd);
return 1;
}
buffer[bytesReceived] = '\0';
cout << "Received from client: " << buffer << endl;
const char *response = "Message received";
send(client_fd, response, strlen(response), 0);
close(client_fd);
close(server_fd);
return 0;
}

复制代码

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <iostream>
#include <cstring>
using namespace std;
int main() {
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
cerr << "Error creating socket" << endl;
return 1;
}
struct sockaddr_in server_addr;
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(9090);
server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
if (connect(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
cerr << "Error connecting to server" << endl;
close(sockfd);
return 1;
}
const char *msg = "Hello, server!";
send(sockfd, msg, strlen(msg), 0);
char buffer[256];
ssize_t bytesReceived = recv(sockfd, buffer, sizeof(buffer) - 1, 0);
if (bytesReceived == -1) {
cerr << "Error receiving data" << endl;
} else {
buffer[bytesReceived] = '\0';
cout << "Received from server: " << buffer << endl;
}
close(sockfd);
return 0;
}

复制代码