指针3

字符数组与字符串

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int main(int argc, char* argv[])
{
	char arr[6] = {'A','B','C','D','E','F'};
	
	char names[] = "ABCDE";

	getchar();
	return 0;

}

image-20231110093915024

编译器在字符串的结尾添加\0作为结束标记

image-20231110094119215

常见字符串操作

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// Test.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
//返回字符的长度
int strlen(char* s)
{
	int ret=0;
	while(*s!=0)
	{
		ret++;
		s++;
	}
	return ret;
}
//交换两个字符
char* strcpy (char* dest, char* src)
{
	char* ret=dest;
	while((*dest++)=(*src++));
	return ret;
}
//拼接两个字符
char* strcat (char* dest, char* src)
{
	char* ret=dest;
	while(*dest!=0)
	{
		dest++;	
	}
	while((*dest++)=(*src++));
	return ret;
}
//比较两个字符是否相等
int strcmp ( char* s1, char* s2)
{	
	while(*s1 != '\0' && *s2 != '\0')
	{
		if(*s1!=*s2)
		{
		return 1;
		}
		s1++;
		s2++;
	}
	if(*s1 == '\0' && *s2 == '\0')
	{
		return 0;
	}
	else
	{
		return 1;
	}

}

int main(int argc, char* argv[])
{
	char arr[]="china";
	char arr1[]="xyz";
	
	
	printf("%s",strcat(arr,arr1));

	getchar();
	return 0;

}

寻址练习

查找char类型数据里为0x64的地址并打印出来

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#include "stdafx.h"

char arr[90] = {
  0x8d, 0x94, 0x31, 0xa6, 0xfa, 0x2c, 0xd1, 0xe0, 0x57, 0x84,
  0xed, 0xbb, 0x41, 0x6f, 0xe5, 0x67, 0xe8, 0x82, 0xb6, 0x2e,
  0x7a, 0x55, 0xcb, 0x76, 0x3d, 0xd9, 0x8c, 0xae, 0xbc, 0x4b,
  0x52, 0xf4, 0x70, 0xea, 0x6d, 0x3e, 0x9b, 0x6b, 0x97, 0x10,
  0x4f, 0x8b, 0x5e, 0x26, 0xce, 0x9c, 0x16, 0xc5, 0x85, 0x90,
  0x2f, 0x1c, 0xd7, 0xa5, 0x28, 0x62, 0x1a, 0xf1, 0x14, 0x7e,
  0xb0, 0xfd, 0xe7, 0xac, 0x98, 0x9e, 0xda, 0x75, 0xb2, 0xec,
  0xc3, 0xd3, 0x72, 0x9d, 0x46, 0xf9, 0xcf, 0xdb, 0x13, 0x7b,
  0x65, 0x3c, 0x23, 0xf2, 0x60, 0x2b, 0xab, 0xa2, 0x83, 0x64
};

void fun()
{

	for(int i=0;i<90;i++)
	{
		if(arr[i]==0x64)
		{
			printf("%x\n",&arr[i]);
		}
	}

}

int main(int argc, char* argv[])
{

	fun();
	getchar();
	return 0;

}

查找int类型数据里为0x64的地址并打印出来

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// Test.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

char arr[100] = {
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x07,0x09,					
0x00,0x20,0x10,0x03,0x03,0x0C,0x00,0x00,0x44,0x00,					
0x00,0x33,0x00,0x47,0x0C,0x0E,0x00,0x0D,0x00,0x11,					
0x00,0x00,0x00,0x02,0x64,0x00,0x00,0x00,0xAA,0x00,					
0x00,0x00,0x64,0x00,0x00,0x00,0x00,0x00,0x00,0x00,					
0x00,0x00,0x02,0x00,0x74,0x0F,0x41,0x00,0x00,0x00,					
0x01,0x00,0x00,0x00,0x05,0x00,0x00,0x00,0x0A,0x00,					
0x00,0x02,0x74,0x0F,0x41,0x00,0x06,0x08,0x00,0x00,					
0x00,0x00,0x00,0x64,0x00,0x0F,0x00,0x00,0x0D,0x00,					
0x00,0x00,0x23,0x00,0x00,0x64,0x00,0x00,0x64,0x00					

};

void fun()
{
	char* p=arr;
	

	for(int i=0;i<97;i++)
	{
		if(*(int*)(p+i)==100)//先以一字节的方式查询所有数据，再转化为四字节指针来满足宽度需求
		{
		printf("%x\n",(p+i));
		}

		
	}

}

int main(int argc, char* argv[])
{

	fun();
	getchar();
	return 0;

}

image-20231110094410162