这里有一些代码可以按照您想要的方式工作。您必须将 std::couts current rdbuf() 替换为文件流之一，然后将其重置：
void write_to_file(function<void()>test_func) {
ofstream ofile;
ofile.open("abc.txt");
std::streambuf* org = cout.rdbuf(); // Remember std::cout's old state
cout.rdbuf(ofile.rdbuf()); // Bind it to the output file stream
test_func(); // Simply call the anonymous function
cout.rdbuf(org); // Reset std::cout's old state
ofile.close();
}
在这里您可以看到它按预期运行：Demo
要克服函数签名变化的问题，您可以使用委托 lambda 函数：
void test_func2(double a, int b) {
cout << a << " * " << b << " = " << (a * b) << endl;
}
int main() {
// Create a lambda function that calls test_func2 with the appropriate parameters
auto test_func_wrapper = []() {
test_func2(0.356,6);
};
write_to_file(test_func_wrapper); // <<<<< Pass the lambda here
// You can also forward the parameters by capturing them in the lambda definition
double a = 0.564;
int b = 4;
auto test_func_wrapper2 = [a,b]() {
test_func2(a,b);
};
write_to_file(test_func_wrapper2);
return 0;
}
Demo
您甚至可以使用一个小助手类来做到这一点，它概括了任何std::ostream 类型的情况：
class capture {
public:
capture(std::ostream& out_, std::ostream& captured_) : out(out_), captured(captured_), org_outbuf(captured_.rdbuf()) {
captured.rdbuf(out.rdbuf());
}
~capture() {
captured.rdbuf(org_outbuf);
}
private:
std::ostream& out;
std::ostream& captured;
std::streambuf* org_outbuf;
};
void write_to_file(function<void()>test_func)
{
ofstream ofile;
ofile.open("abc.txt");
{
capture c(ofile,cout); // Will cover the current scope block
test_func();
}
ofile.close();
}
Demo
所以关于你的comment：
当然，但我需要一些东西来存储这些 cout，或者也许有另一种完全不同的方式，而不是使用 test_func() 来处理这个过程？
我们现在手头有一切来做这件事
#include <iostream>
#include <fstream>
#include <functional>
#include <string>
#include <sstream>
using namespace std;
void test_func1(const std::string& saySomething) {
cout << saySomething << endl;
}
void test_func2(double a, int b) {
cout << "a * b = " << (a * b) << endl;
}
class capture {
public:
capture(std::ostream& out_, std::ostream& captured_) : out(out_), captured(captured_), org_outbuf(captured_.rdbuf()) {
captured.rdbuf(out.rdbuf());
}
~capture() {
captured.rdbuf(org_outbuf);
}
private:
std::ostream& out;
std::ostream& captured;
std::streambuf* org_outbuf;
};
int main() {
std::string hello = "Hello World";
auto test_func1_wrapper = [hello]() {
test_func1(hello);
};
double a = 0.356;
int b = 6;
auto test_func2_wrapper = [a,b]() {
test_func2(a,6);
};
std::stringstream test_func1_out;
std::stringstream test_func2_out;
std::string captured_func_out;
{ capture c(test_func1_out,cout);
test_func1_wrapper();
}
{ capture c(test_func2_out,cout);
test_func2_wrapper();
}
captured_func_out = test_func1_out.str();
cout << "test_func1 wrote to cout:" << endl;
cout << captured_func_out << endl;
captured_func_out = test_func2_out.str();
cout << "test_func2 wrote to cout:" << endl;
cout << captured_func_out << endl;
}
当然还有 Demo。