使用std::ostream作为打印函数的参数

我一直习惯cout打印声明,但现在我想学习打印passing the stream,就像 void print(std::ostream&) const;我目前的打印功能一样

template 

void Mystack::print()
{
    for (int i = 0; i <= top; i++)
    {
        std::cout <

我有两个问题:


从我上面实现的普通打印功能切换到使用的打印功能有什么好处ostream.
如何ostream在我的功能中实现.我试图ostream从互联网来源了解但无法理解.请帮忙.


以下是完整的运行代码:

//*************STACK CODE***************//

//VERY GOOD EXAMPLE TO UNDERSTAND RULE OF THREE FOR BEGINEERS http://www.drdobbs.com/c-made-easier-the-rule-of-three/184401400
//RULE OF THREE : Video : https://www.youtube.com/watch?v=F-7Rpt2D-zo
//Thumb Rule : Whenever we have class which has members pointing to heap space we should implement Rule of three.
//Concepts : Shallow Copy and Deep Copy

#include 
template 
class Mystack
{
private:
    T *input;
    int top;
    int capacity;
public:
    Mystack();
    ~Mystack();
    void push(T const& x);
    void pop();
    T& topElement() const;
    bool isEmpty() const;
    void print();
};
template 
Mystack::Mystack()
{
    top = -1;
    capacity = 5;
    input = new T[capacity];
}
template 
Mystack::~Mystack() //Since we are using destructor explictly we need to apply Rule of 3
{
    delete [] input;
}
template 
void Mystack::push(T const& x)  //Passing x by Const Reference // Valus of x cannot be changed now in the function!
{
    if (top + 1 == capacity)
    {
        T *vec = new T[capacity * 2];
        for (int i = 0; i <= top; i++)
        {
            vec[i] = input[i];
        }
        delete []input; // Avoiding Memory Leak.
        input = vec;
        capacity *= capacity;
    }
    top++;
    std::cout <
void Mystack::pop()
{
    if (isEmpty())
    {
        throw std::out_of_range("Stack Underflow");
    }
    else
    {
        std::cout <<"The popped element is" <
bool Mystack::isEmpty() const
{
    if (top == -1)
    {
        std::cout <<"Is Empty" <
T& Mystack::topElement() const
{
    if (top == -1)
    {
        throw std::out_of_range("No Element to Display");
    }
    else
    {
        std::cout <<"The top element is : " <
void Mystack::print()
{
    for (int i = 0; i <= top; i++)
    {
        std::cout < s1;
    Mystack s2;
    Mystack s3;
    int choice;
    int int_elem;
    float float_elem;
    char char_elem;
    std::cout <<"Enter the type of stack" <> choice;
    if (choice == 1)
    {
        int  ch = 1;
        while (ch > 0)
        {
            std::cout <<"\n1. Push ";
            std::cout <<"2. Top ";
            std::cout <<"3. IsEmpty ";
            std::cout <<"4. Pop ";
            std::cout <<"5. Exit ";
            std::cout <<"6. Print"<> ch;
            switch (ch)
            {
            case 1:
                std::cout <<"Enter the number to be pushed" <> int_elem;
                s1.push(int_elem);
                break;
            case 2:
                std::cout <<"Get the TOP Element" < 0)
        {
            std::cout <<"\n1. PUSH" <> ch;
            switch (ch)
            {
            case 1:
                std::cout <<"Enter the number to be pushed" <> float_elem;
                s2.push(float_elem);
                break;
            case 2:
                std::cout <<"Get the TOP Element" < 0)
        {
            std::cout <<"\n1. PUSH" <> ch;
            switch (ch)
            {
            case 1:
                std::cout <<"Enter the number to be pushed" <> char_elem;
                s3.push(char_elem);
                break;
            case 2:
                std::cout <<"Get the TOP Element" <

    

  




  
  
  

    

      

        MondKin..
         7
      
      
The benefit of switching to the ostream version is that in the case you later need to print to other places besides std::cout then you can do it with the same function implementation, whereas in this moment if you want to print to a file you would need to use a different function.

An example of how to implement it is instead of doing this:

void print()
{   
    std::cout <<"Print something always to cout" <

You do this (notice we are passing a reference):

void print(std::ostream& os) 
{   
    os <<"Print something to wherever the caller wants to" <

Now instead of calling the function like:

print();


你将调用这样的函数打印到cout:

print(std::cout);


或者像这样打印到文件:

std::ofstream some_file("test.txt");
a.print(some_file);


请参阅,使用相同的功能,您可以决定打印的位置.


1> MondKin..：
The benefit of switching to the ostream version is that in the case you later need to print to other places besides std::cout then you can do it with the same function implementation, whereas in this moment if you want to print to a file you would need to use a different function.

An example of how to implement it is instead of doing this:

void print()
{   
    std::cout <<"Print something always to cout" <

You do this (notice we are passing a reference):

void print(std::ostream& os) 
{   
    os <<"Print something to wherever the caller wants to" <

Now instead of calling the function like:

print();


你将调用这样的函数打印到cout:

print(std::cout);


或者像这样打印到文件:

std::ofstream some_file("test.txt");
a.print(some_file);


请参阅,使用相同的功能,您可以决定打印的位置.