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remove typedef

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Jidong Xiao
2024-02-01 20:41:06 -05:00
parent 0d2df42f23
commit 4ee278dd8c
1 changed files with 15 additions and 21 deletions
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36
lectures/08_vector_implementation/README.md
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@@ -15,13 +15,13 @@ In creating our own version of the STL vector class, we will start by considerin
```cpp ```cpp
public: public:
// MEMBER FUNCTIONS AND OTHER OPERATORS // MEMBER FUNCTIONS AND OTHER OPERATORS
T& operator[] (size_type i); T& operator[] (unsigned int i);
const T& operator[] (size_type i) const; const T& operator[] (unsigned int i) const;
void push_back(const T& t); void push_back(const T& t);
void resize(size_type n, const T& fill_in_value = T()); void resize(unsigned int n, const T& fill_in_value = T());
void clear(); void clear();
bool empty() const; bool empty() const;
size_type size() const; unsigned int size() const;
``` ```
- To implement our own generic (a.k.a. templated) vector class, we will implement all of these operations, - To implement our own generic (a.k.a. templated) vector class, we will implement all of these operations,
@@ -77,13 +77,7 @@ member function should return,
- m_alloc is the total number of slots in the dynamically allocated block of memory. - m_alloc is the total number of slots in the dynamically allocated block of memory.
Drawing pictures, which we will do in class, will help clarify this, especially the distinction between m_size and m_alloc. Drawing pictures, which we will do in class, will help clarify this, especially the distinction between m_size and m_alloc.
## 8.5 Typedefs ## 8.5 operator[]
- Several types are created through typedef statements in the first public area of Vec. Once created the names
are used as ordinary type names. For example Vec<int>::size type is the return type of the size() function,
defined here as an unsigned int.
## 8.6 operator[]
Access to the individual locations of a Vec is provided through operator[]. Syntactically, use of this operator Access to the individual locations of a Vec is provided through operator[]. Syntactically, use of this operator
is translated by the compiler into a call to a function called operator[]. For example, if v is a Vec<int>, is translated by the compiler into a call to a function called operator[]. For example, if v is a Vec<int>,
@@ -99,7 +93,7 @@ In most classes there are two versions of operator[]:
– A non-const version returns a reference to m_data[i]. This is applied to non-const Vec objects. – A non-const version returns a reference to m_data[i]. This is applied to non-const Vec objects.
– A const version is the one called for const Vec objects. This also returns m_data[i], but as a const reference, so it can not be modified. – A const version is the one called for const Vec objects. This also returns m_data[i], but as a const reference, so it can not be modified.
## 8.7 Default Versions of Assignment Operator and Copy Constructor Are Dangerous! ## 8.6 Default Versions of Assignment Operator and Copy Constructor Are Dangerous!
Before we write the copy constructor and the assignment operator, we consider what would happen if we didn’t write them. Before we write the copy constructor and the assignment operator, we consider what would happen if we didn’t write them.
- C++ compilers provide default versions of these if they are not provided. These defaults just copy the values - C++ compilers provide default versions of these if they are not provided. These defaults just copy the values
@@ -114,7 +108,7 @@ In other words, it would construct each member variable from the corresponding m
dangerous and incorrect behavior for the Vec class. We don’t want to just copy the m_data pointer. We really dangerous and incorrect behavior for the Vec class. We don’t want to just copy the m_data pointer. We really
want to create a copy of the entire array! Let’s look at this more closely... want to create a copy of the entire array! Let’s look at this more closely...
## 8.8 Exercise ## 8.7 Exercise
Suppose we used the default version of the assignment operator and copy constructor in our Vec<T> class. What Suppose we used the default version of the assignment operator and copy constructor in our Vec<T> class. What
would be the output of the following program? Assume all of the operations except the copy constructor behave as would be the output of the following program? Assume all of the operations except the copy constructor behave as
@@ -131,7 +125,7 @@ cout << u[i] << " " << v[i] << endl;
Explain what happens by drawing a picture Explain what happens by drawing a picture
of the memory of both u and v. of the memory of both u and v.
## 8.9 Classes With Dynamically Allocated Memory ## 8.8 Classes With Dynamically Allocated Memory
For Vec (and other classes with dynamically-allocated memory) to work correctly, each object must do its own For Vec (and other classes with dynamically-allocated memory) to work correctly, each object must do its own
dynamic memory allocation and deallocation. We must be careful to keep the memory of each object instance dynamic memory allocation and deallocation. We must be careful to keep the memory of each object instance
@@ -143,7 +137,7 @@ the object itself goes out of scope (through what’s called a destructor).
– Assignment operator – Assignment operator
– Destructor – Destructor
## 8.10 The “this” pointer ## 8.9 The “this” pointer
All class objects have a special pointer defined called this which simply points to the current class object, and All class objects have a special pointer defined called this which simply points to the current class object, and
it may not be changed. it may not be changed.
@@ -153,7 +147,7 @@ it may not be changed.
- Check to see when an assignment is self-referencing. - Check to see when an assignment is self-referencing.
- Return a reference to the current object. - Return a reference to the current object.
## 8.11 Copy Constructor ## 8.10 Copy Constructor
This constructor must dynamically allocate any memory needed for the object being constructed, copy the This constructor must dynamically allocate any memory needed for the object being constructed, copy the
contents of the memory of the passed object to this new memory, and set the values of the various member contents of the memory of the passed object to this new memory, and set the values of the various member
@@ -161,7 +155,7 @@ variables appropriately.
- Exercise: In our Vec class, the actual copying is done in a private member function called copy. Write the - Exercise: In our Vec class, the actual copying is done in a private member function called copy. Write the
private member function copy. private member function copy.
## 8.12 Assignment Operator ## 8.11 Assignment Operator
Assignment operators of the form: Assignment operators of the form:
```cpp ```cpp
@@ -203,13 +197,13 @@ A = B;
These two lines will: the first line creates the object A, and the second line invokes the assignment operator. These two lines will: the first line creates the object A, and the second line invokes the assignment operator.
## 8.13 Destructor (the “constructor with a tilde/twiddle”) ## 8.12 Destructor (the “constructor with a tilde/twiddle”)
The destructor is called implicitly when an automatically-allocated object goes out of scope or a dynamically allocated object is deleted. It can never be called explicitly! The destructor is called implicitly when an automatically-allocated object goes out of scope or a dynamically allocated object is deleted. It can never be called explicitly!
- The destructor is responsible for deleting the dynamic memory “owned” by the class. - The destructor is responsible for deleting the dynamic memory “owned” by the class.
- The syntax of the function definition is a bit weird. The ~ has been used as a bit-wise inverse or logic negation in other contexts. - The syntax of the function definition is a bit weird. The ~ has been used as a bit-wise inverse or logic negation in other contexts.
## 8.14 Increasing the Size of the Vec ## 8.13 Increasing the Size of the Vec
- push_back(T const& x) adds to the end of the array, increasing m_size by one T location. But what if the allocated array is full (m_size == m_alloc)? - push_back(T const& x) adds to the end of the array, increasing m_size by one T location. But what if the allocated array is full (m_size == m_alloc)?
1. Allocate a new, larger array. The best strategy is generally to double the size of the current array. Why? 1. Allocate a new, larger array. The best strategy is generally to double the size of the current array. Why?
@@ -219,12 +213,12 @@ The destructor is called implicitly when an automatically-allocated object goes
- Only when we are sure there is enough room in the array should we actually add the new object to the back of the array. - Only when we are sure there is enough room in the array should we actually add the new object to the back of the array.
## 8.15 Exercises ## 8.14 Exercises
- Finish the definition of Vec::push_back. - Finish the definition of Vec::push_back.
- Write the Vec::resize function. - Write the Vec::resize function.
## 8.16 Leetcode Exercises ## 8.15 Leetcode Exercises
- [Leetcode problem 27: Remove Element](https://leetcode.com/problems/remove-element/). Solution: [p27_removeelement.cpp](../../leetcode/p27_removeelement.cpp) - [Leetcode problem 27: Remove Element](https://leetcode.com/problems/remove-element/). Solution: [p27_removeelement.cpp](../../leetcode/p27_removeelement.cpp)
- [Leetcode problem 263: Ugly Number](https://leetcode.com/problems/ugly-number/). Solution: [p263_uglynumber.cpp](../../leetcode/p263_uglynumber.cpp) - [Leetcode problem 263: Ugly Number](https://leetcode.com/problems/ugly-number/). Solution: [p263_uglynumber.cpp](../../leetcode/p263_uglynumber.cpp)