C++基础学习之输入输出流详解

#include <iostream>
using namespace std;
int main(){
    int a, b;
    cout << "请输入两个整数：" << endl;
    cin >> a >> b;
    cout << "您输入的两个整数分别为：" << a << "和" << b << endl;
    return 0;
}

#include <iostream>
using namespace std;
int main(){
    cout << "Hello, world!" << endl;
    return 0;
}

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(){
    string fileName;
    cout << "请输入文件名：" << endl;
    cin >> fileName;
    ifstream inFile(fileName.c_str());
    if(!inFile.is_open()){
        cout << "打开文件失败！" << endl;
    }else{
        string tempStr;
        while(getline(inFile, tempStr)){
            cout << tempStr << endl;
        }
    }
    inFile.close();
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(){
    ofstream outFile("test.txt");
    if(!outFile.is_open()){
        cout << "打开文件失败！" << endl;
    }else{
        outFile << "This is a test file." << endl;
        outFile << "It is used for input and output operations." << endl;
    }
    outFile.close();
    return 0;
}

#include <iostream>
#include <iomanip>
using namespace std;
int main(){
    double val = 3.1415926;
    cout << fixed << setprecision(3) << val << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
int main(){
    string s1, s2;
    cout << "请输入两个字符串：" << endl;
    cin >> s1 >> s2;
    cout << "您输入的两个字符串分别为：" << s1 << "和" << s2 << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
int main(){
    string s;
    cout << "请输入一个字符串：" << endl;
    getline(cin, s);
    cout << "您输入的字符串为：" << s << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
int main(){
    string s1, s2;
    cout << "请输入两个字符串，使用空格分隔：" << endl;
    cin >> s1 >> s2;
    cout << "您输入的两个字符串分别为：" << s1 << "和" << s2 << endl;
    string s3 = "hello", s4 = "world";
    cout << "使用空格连接两个字符串得到结果：" << s3 << " " << s4 << endl;
    return 0;
}