C基础day10

#include<myhead.h>
#define Max_Size 100


//strlen函数
int my_strlen(const char *str)
{
	int len = 0;
	while(*str++ !='\0')
	{
		len++;
	}
	return len;
}

//strcpy函数
void my_strcpy(char *dest,const char *src)
{
	while(*src) //遍历src将src赋值给dest
	{
		*dest++ = *src;
		src++;
	}
	*dest = '\0';
}

//strcmp
int strcmp(const char *s1,const char *s2)
{
	while(*s1) //遍历s1和s2比较
	{
		if(*s1 == *s2)
		{
			s1++;
			s2++;
		}
		else
			return *s1 - *s2;
		if(*s1 == '\0')
			return 0;
	}

}

//strcat
char *my_strcat(char *dest,const char *src)
{
	int i=0;
	while(*dest) //遍历到dest末尾
	{
		dest++;
	}
	while(*src) //遍历src连接到dest的末尾
	{
		*dest++ =*src++;
	}
	*dest = '\0';
}

//子串
void my_strstr(const char *dest,const char *src)
{
	while(*src) //遍历src
	{
		while(*src == *dest) //当dest首位等于src的某一位开始遍历dest
		{
			src++;
			dest++;
			if(*dest == '\0') //dest遍历结束标志,说明包含
			{
				printf("包含\n");
				break;
			}
			else 
			{
				continue;
			}
		
		}
		src++;
		if(*dest != '\0' && *src == '\0') //dest已经遍历结束,src还没遍历结束说明不包含
			printf("不包含\n");
	}
}


int main(int argc, const char *argv[])
{
	char str[Max_Size];
	char dest[Max_Size];
	char src[Max_Size];
	//strlen
	//输入字符串
	printf("strlen\n");
	printf("请输入字符串：");
	gets(str);
	int res = my_strlen(str);
	//输出
	printf("字符串长度为：%d\n",res);


	//strcpy	
	printf("strcpy\n");

	printf("请输入字符串src：");
	gets(src);
	printf("请输入字符串dest：");
	gets(dest);
	printf("src:");
	puts(src);
	printf("dest:");
	puts(dest);
	my_strcpy(dest,src);
	printf("复制后的dest：");
	puts(dest);

	//strcmp
	printf("strcmp\n");

	printf("请输入字符串1:");
	gets(dest);
	printf("请输入字符串2:");
	gets(src);
	int value = strcmp(dest,src);
	printf("%d\n",value);

	//strcat	
	printf("strcat\n");

	printf("请输入字符串1:");
	gets(dest);
	printf("请输入字符串2:");
	gets(src);
	my_strcat(dest,src);
	puts(dest); 

	//是否包含子串
	printf("strstr\n");

	printf("请输入字符串1:");
	gets(dest);
	printf("请输入字符串2:");
	gets(src);
	printf("字符串2是否包含字符串1：");
	my_strstr(dest,src);
	




	return 0;
}