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C++基础知识详解：指针使用与内存操作

最新推荐文章于 2023-04-13 10:16:35 发布

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本文深入探讨了C++中指针的基本概念、声明与使用方法，包括如何通过指针访问和修改内存中的数据。通过具体代码示例，详细展示了如何将值赋给指针、通过指针进行值的读写操作以及不同类型指针的用法。重点突出了C++指针在内存管理中的重要性及其实现复杂性的关键特性。

C++ basics

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In C++, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.

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C++ does not recognize the end of the line as a terminator.

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C++ KEY WORDS

\asm else          new                         this
auto                enum operator throw
bool    explicit       private                    true
break export         protected               try
case extern         public                    typedef
catch              false           register                  typeid
char                float           reinterpret_cast    typename
class      for               return                     union
const    friend         short                       unsigned
const_cast    goto            signed                   using
continue        if                  sizeof                     virtual
default           inline          static void
delete            int                static_cast volatile
do                   long            struct    wchar_t
double           mutable      switch                    while
dynamic_cast               namespace    template

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A local variable is known only to the function in which it is declared.

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A formal parameter is a local variable that receives the value of an arument.

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Now, it is the most interesting part-pointer.

Pointers are without doubt one of the most important-and troublesome-aspects of C++. In fact, a large measure of C++'s power is derived from pointers. They allow C++ to support such things as linked lists and dynamic memory allocation.

A pointer is a variable that contains the address of another object.

To declare P to be a pointer to an integer, use the declaration: int *P

a pointer to a float, use the declaration: float *P

There are twp special operators that are used with pointers: * and &.

Let's see the simple example.

#include<iostream>

using namespace std;

int main()

{

int balance;

int *balptr;

int value;

balance = 300;

balptr = &balance;

value = *balptr;

cout << " balance is : "<< value << '\n'<<endl;

return 0;

}

The output is shown here.
balance is: 3200

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The base type of pointer is important. It determine the how many bytes of address the compiler would transfer for the pointer types.

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Assigning Values Through a Pointer

#include <iostream>
using namespace std;
int main()
{
int *p, num;
p = &num;
*p = 100;
cout << num << ' ';
(*p)++;//Here is call back the value which is stored in the p.
cout << num << ' ';
(*p)--;
cout << num << '\n';
return 0;
}
The output from the program is shown here.
100 101 100

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