C++中的输出空间？

int num = 10;
cout << "The number is: " << num << endl;

#include <fstream>
using namespace std;

int main() {
    ofstream outputFile;
    outputFile.open("output.txt"); // 打开文件output.txt

    if (outputFile.is_open()) {
        outputFile << "Hello, World!" << endl;
        outputFile.close(); // 关闭文件
    } else {
        cout << "Failed to open the file." << endl;
    }

    return 0;
}

#include <sstream>
using namespace std;

int main() {
    ostringstream oss;
    int num = 10;
    string str = "Hello";

    oss << "The number is: " << num << ", and the string is: " << str;

    string output = oss.str();
    cout << output << endl;

    return 0;
}