字符串的拷贝strcpy函数

字符串的拷贝strcpy函数

• 方法一

#include<stdio.h>
#include<string.h>
#include<assert.h>
void my_strcpy(char* dest, const char* src)
{
	assert(dest != NULL && src != NULL);
	int i = 0;
	while (src[i]!='\0')//*src!='\0'
	{
		dest[i] = src[i];//*dest++=*src++;
		++i;
	}
	dest[i] = '\0';
}
int main()
{
	char stra[30] = { "hello" };
	char strb[30];
	char strc[30];
	my_strcpy(strb, stra);
	my_strcpy(strc, strb);
	printf("%s\n", strb);
	printf("%s\n", strc);
	return 0;
}

• 方法二

void my_strcpy(char* dest, const char* src)
{
	assert(dest != NULL && src != NULL);
	while (*src!='\0')
	{
	*dest=*src;
		dest++;
		src++;//也可直接写成*dest++=*src++;
	}
	*dest = '\0';
}
int main()
{
	char stra[30] = { "hello" };
	char strb[30];
	char strc[30];
	my_strcpy(strb, stra);
	my_strcpy(strc, strb);
	printf("%s\n", strb);
	printf("%s\n", strc);
	return 0;
}

• 函数的连续拷贝

char* my_strcpy(char* dest, const char* src)
{
	assert(dest != NULL && src != NULL);
	char* p=dest;//用指针保存地址
	while (*src!='\0')
	{
	*dest=*src;
		dest++;
		src++;//也可直接写成*dest++=*src++;
	}
	*dest = '\0';
	return p;
}
int main()
{
	char stra[30] = { "hello" };
	char strb[30];
	char strc[30];
	my_strcpy(strc,my_strcpy(strb, stra));
	printf("%s\n", strb);
	printf("%s\n", strc);
	return 0;
}