/**************************************************

實驗四?串運算

1、	實現串賦值、串比較、求串長、串聯接以及求子串這5種基本操作。
2、	能利用上述實現的基本操作完成置換Replace?（&S?T?V）以及從串中刪除一段子串StrDelete（&Sposlen）的操作。
3、	以上要求實現的操作不能直接使用C語言提供的函數（gets（），puts（）除外）完成。
4、	所寫源代碼編程風格良好，有詳細注釋。
5、	程序運行界面良好，使用菜單實現每個基本操作。

****************************************************/

#include
#include
#include
#define	NULL	0
#define	MAX	20
#define	TRUE	1
#define	FALSE	0

typedef	struct{
	char*	str;
	int	length;
}HString;

void	menu（）{
	printf（“\n“）;
	printf（“\n??????===================================================================“）;
	printf（“\n?????|???????????????????????????????????????????????????????????????????|“）;
	printf（“\n?????|???Welcome!Here?is?the?menu..??????????????????????????????????????|“）;
	printf（“\n?????|???1.??Initialize?a?string;????????????????????????????????????????|“）;
	printf（“\n?????|???2.??Copy?a?string;??????????????????????????????????????????????|“）;
	printf（“\n?????|???3.??Compare?two?string;?????????????????????????????????????????|“）;
	printf（“\n?????|???4.??Get?length?of?a?string;?????????????????????????????????????|“）;
	printf（“\n?????|???5.??Connect?two?strings;????????????????????????????????????????|“）;
	printf（“\n?????|???6.??Get?sub-string;?????????????????????????????????????????????|“）;
	printf（“\n?????|???7.??Replace?in?string;??????????????????????????????????????????|“）;
	printf（“\n?????|???8.??Delete?sub-string;??????????????????????????????????????????|“）;
	printf（“\n?????|???9.??exit.???????????????????????????????????????????????????????|“）;
	printf（“\n?????|???????????????????????????????????????????????????????????????????|“）;
	printf（“\n??????===================================================================“）;
	printf（“\n\nPlease?choose?which?to?do:??????“）;
}

int	InitStr（HString*?s）{
	int?i=0;
	char	a[20];
	gets（a）;
	for（;a[i]!=‘\0‘;i++）;
	s->length=i;
	if（!s->str）?free（s->str）;
	if（!i）?s->str=NULL;
	else{
	s->str=（char*）malloc（（s->length）*sizeof（char））;
	if（!（s->str））?{printf（“Initialize?failed!!\n“）;return	FALSE;}
	for（i=0;ilength;i++）?s->str[i]=a[i];
	}
	return?TRUE;
}

void	EmptyInit（HString*?s）{
	s->length=0;
	s->str=NULL;
}

int	CopyString（HString*?sHString?s1）{
	int?i=0;
	s->length=s1.length;
	if（!s->str）?free（s->str）;
	if（!s1.length）?s->str=NULL;
	else{
	s->str=（char*）malloc（（s->length）*sizeof（char））;
	if（!（s->str））?{printf（“Copy?string?failed!!\n“）;return	FALSE;}
	for（i=0;ilength;i++）?s->str[i]=s1.str[i];
	}
	return?TRUE;
}

int	CmpString（HString?s1HString?s2）{
	int?i;
	for（i=0;i	return?s1.length-s2.length;
}

int	GetLengthString（HString?s）{
	return	s.length;
}

int	Concat（HString*?sHString?s1HString?s2）{
	int	i=0j=0;
	s->length=s1.length+s2.length;
	if（!s->str）?free（s->str）;
	s->str=（char*）malloc（（s->length）*sizeof（char））;
	if（!