指针笔记

深藏阁楼爱情的钟 2022-10-23 08:02 16阅读 0赞

### 指针笔记 ###

*  指针使用
 *  指针赋值
 *   *  使用事项
 *  指针作为函数参数
 *  指针与数组
 *  用数组名作为函数参数
 *  多维数组与指针
 *  用指向函数的指针作函数参数
 *  返回指针值的函数

# 指针使用 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70]

# 指针赋值 #

#include <stdio.h>
    
    void main()
    
    { 
    	int *a,*b;
    	int  i=1;int t=2;
    
    	a = &i; 
    	b = &t;
    
    	printf("a=%d,b=%d\n",*a,*b);
    
    	a = b;  /*a的地址会变为b的地址，即t的地址*/
     
    	printf("a=%d,b=%d\n",*a,*b);
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 1]

## 使用事项 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 3]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 4]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 5]

#include <stdio.h>
    
    void main()
    
    { 
    	int *a,*b;
    	int  i=1;int t=2;
    
    	a = &i;
    	b = &t;
    
    	(*a)++;   /*相当于i++*/
    	(*b)++;
    
    	printf("a = %d,b = %d\n",*a,*b);
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 6]

# 指针作为函数参数 #

#include <stdio.h>
    
    void swap(int *n,int *m);
    
    void main()
    
    { 
    	int a,b;
    	scanf("%d,%d",&a,&b);
    	swap(&a,&b);
    	printf("%d > %d\n",a,b);
    }
    
    void swap(int *n,int *m)
    { 
    	int *j;
    	
    	if(*n < *m)
    	{ 
    		n = j;
    		m = n;
    		j = m;
    	}
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 7]

# 指针与数组 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 8]

#include <stdio.h>
    
    void main()
    
    { 
    	int a[2] = { 0,1};
    	int *j,*k;
    
    	j = &a[0];
    	k = a;     
    
    	printf("*j = %d,*k = %d\n",*j,*k);
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 9]

#include <stdio.h>
    
    void main()
    
    { 
    	int a[2] = { 0,1};
    	int *j,*k;
    	int n,m;
    
    	j = &a[0];
    	k = a;
    
    	n = *(j+1);
    	m = *(k+1);
    
    	printf("*j = %d,*k = %d\n",*j,*k);
    	printf("n = %d,m = %d\n",n,m);
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 10]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 11]  
**上下两幅图可以发现 p++ 等同于 (p+i)  
然后输出\*p**  
\***(p+i)**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 12]

**p++,因为整形占4个字节**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 13]

# 用数组名作为函数参数 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 14]

#include <stdio.h>
    
    void sort(int *i,int n);
    
    void main()
    
    { 
    	int a[10] = { 0,1,2,3,4,5,6,7,8,9};
    	int j;
    	sort(a,10);
    	for(j=0;j<10;j++)
    	{ 
    		printf("%d\n",a[j]);
    	}
    }
    
    void sort(int *i,int n)
    { 
    	int j,k,t;
    	for(j=0;j<n-1;j++)
    	{ 
    		for(k=j+1;k<n;k++)
    		{ 
    			if(*(i+j) < *(i+k))
    			{ 
    				t = *(i+j);
    				*(i+j) = *(i+k);
    				*(i+k) = t;
    			}
    		}
    	}
    	
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 15]

# 多维数组与指针 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 16]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 17]  
![\#\# 三维数组][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 18]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 19]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 20]

# 用指向函数的指针作函数参数 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 21]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 22]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 23]  
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# 返回指针值的函数 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p5eTEzMDk4OA_size_16_color_FFFFFF_t_70 26]  
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