1.編寫頭文件
#define _CRT_SECURE_NO_WARNINGS
//#pragmawarning(disable:4996)
#include
#include
#include
struct CString
{
char *p; //保存字符串首地址
int reallength; //實際長度
};
typedef struct CString mystring;//簡寫
//原封不動初始化
void init(mystring *string);
//開辟長度，內存清零
void initwithlength(mystring *string, int length);
//初始化並拷貝字符串
void initwithstring(mystring *string, char *copystring);
//打印
void printfstring(mystring *string);
//增加字符
void backaddchar(mystring *string, char ch);
//增加字符串
void backaddstring(mystring *string, char*str);
//執行指令
void run(mystring *string);
//返回第一個找到的字符的地址
char * findfirstchar(mystring *string, char ch);
//返回第一個找到的字符串的地址
char * findfirststring(mystring *string, char *str);
//刪除第一個找到的字符
int deletefirstchar(mystring *string, const char ch);
//刪除第一個找到的字符串
int deletefirststring(mystring *string, char * const str);
//任意增加字符
void addchar(mystring *string, char ch, char *pos);
//任意增加字符串
void addstring(mystring *string, char*str, char *pos);
//改變字符
void changefirstchar(mystring *string, const char oldchar, const char newchar);
//改變字符串
void changefirststring(mystring *string, char * const oldstring, char *const newstring);
2.編寫函數實現
#include "mystring.h"
#include "stdio.h"
#include "stdlib.h"
/* 求字符串的長度 */
int mystrlen(char *p)
{
if (p == NULL)
{
return -1;//失敗，
}
int length = 0;
while (*p != '\0')//字符串終止條件
{
length++;//長度自增
p++;//指針不斷向前
}
return length;
}
/*字符串拷貝 */
char *mystrcpy(char *dest, const char *source)//const限定不被意外修改
{
if (dest == NULL || source == NULL)
{
return NULL;//為空沒有必要干活了
}
char * destbak = dest;
while (*source != '\0')//一直拷貝
{
*dest = *source;//賦值字符
source++;
dest++;//指針不斷向前，字符挨個賦值
}
*dest = '\0';//結尾
return destbak;//返回地址
}
/*字符串拼接*/
char *mystrcat(char *dest, const char *source)
{
if (dest == NULL || source == NULL)
{
return NULL;//失敗
}
else
{
char *destbak = dest;//保留地址
while (*dest != '\0')
{
dest++;//指針向前移動
}
//從尾部開始拷貝
while (*source != '\0') //循環被被拷貝的字符串
{
*dest = *source;//字符串賦值
dest++;
source++;
}
*dest = '\0';//結尾
return destbak;
}
}
char * mystrchr(const char *dest, const char ch)
{
if (dest == NULL)
{
return NULL;
}
while (*dest != '\0')
{
if (*dest == ch)
{
return dest;//找到返回地址
}
dest++;
}
return NULL;//返回
}
char *mystrstr(const char * const dest, const char * const findstr)
{
if (dest == NULL || findstr == NULL)
{
return NULL;
}
char *destbak = dest;
char *p = NULL;//保存找到的地址
while (*destbak != '\0')
{
int flag = 1;//假定是相等
char *findstrbak = findstr;
char *nowdestbak = destbak;
while (*findstrbak != '\0')
{
if (*nowdestbak != '\0')
{
if (*findstrbak != *nowdestbak)//有一個不等
{
flag = 0;//賦值為0代表不等
}
nowdestbak++;
findstrbak++;
}
else
{
flag = 0;//設置標識
break;
}
}
if (flag == 1)
{
p = destbak;//當前位置
return p;
}
destbak++;
}
return NULL;
}
void init(mystring *string)
{
string->p = NULL;
string->reallength = 0;//初始化結構體字符串
}
void initwithlength(mystring *string, int length)
{
//string->p =(char *) malloc(sizeof(char)*length);//分配內存
string->p = (char *)calloc(length, sizeof(char));//分配內存並清零
string->reallength = length;//長度
}
void initwithstring(mystring *string, char *copystring)
{
int length = strlen(copystring);//獲取字符串長度
string->p = (char *)calloc(length + 1, sizeof(char));//分配內存
mystrcpy(string->p, copystring);//拷貝字符串
string->reallength = length + 1;//設置長度
}
void backaddchar(mystring *string, char ch)
{
if (mystrlen(string->p) + 1 == string->reallength)//意味著滿了
{
//重新分配內存
string->p = realloc(string->p, string->reallength + 1);
string->reallength += 1;
string->p[string->reallength - 2] = ch;
string->p[string->reallength - 1] = '\0';
}
else
{
int nowlength = mystrlen(string->p);//求出當前長度
string->p[nowlength] = ch;
string->p[nowlength + 1] = '\0';//字符的增加
}
}
void backaddstring(mystring *string, char*str)
{
int nowmystringlength = mystrlen(string->p);//獲取當前長度
int addstringlength = mystrlen(str);//要增加的長度
if (nowmystringlength + addstringlength + 1 > string->reallength)//判定是否越界
{
int needaddlength = nowmystringlength + addstringlength + 1 - (string->reallength);
//printf("%d",needaddlength);
string->p = (char *)realloc(string->p, string->reallength + needaddlength);//增加字符串長度
mystrcat(string->p, str);//拷貝字符串
string->reallength += needaddlength;//增加長度
}
else
{
mystrcat(string->p, str);//拷貝字符串
}
}
void printfstring(mystring *string)
{
printf("\nstring=%s", string->p);//打印字符串
}
void run(mystring *string)
{
system(string->p);//執行指令
}
char * findfirstchar(mystring *string, char ch)
{
char *p = mystrchr(string->p, ch);//查找
return p;
}
char * findfirststring(mystring *string, char *str)
{
char *pres = mystrstr(string->p, str);
return pres;//返回地址
}
int deletefirstchar(mystring *string, const char ch)
{
char *p = mystrchr(string->p, ch);//查找
if (p == NULL)
{
return 0;
}
else
{
char *pnext = p + 1;
while (*pnext != '\0')
{
*p = *pnext; //刪除一個字符整體向前移動
p++;
pnext++;
}
*p = '\0';//字符串要有結尾
return 1;
}
}
int deletefirststring(mystring *string, char * const str)
{
char *pres = mystrstr(string->p, str);//查找
if (pres == NULL)
{
return 0;
}
else
{
int length = mystrlen(str);//求字符串長度
char *pnext = pres + length;//下一個字符
while (*pnext != '\0')
{
*pres = *pnext; //刪除一個字符整體向前移動
pres++;
pnext++;
}
*pres = '\0';//字符串要有結尾
return 1;
}
}
void addchar(mystring *string, char ch, char *pos)
{
if (pos == NULL || string == NULL)
{
return;
}
if (mystrlen(string->p) + 1 == string->reallength)//意味著滿了
{
//重新分配內存
string->p = realloc(string->p, string->reallength + 1);
string->reallength += 1;
int nowlength = mystrlen(string->p);//求出當前長度
int movelength = mystrlen(pos);//求出現在要移動的長度
for (int i = nowlength; i > nowlength - movelength; i--)//移動
{
string->p[i] = string->p[i - 1];//輪詢
}
string->p[nowlength - movelength] = ch;//插入
string->p[nowlength + 1] = '\0';//結尾
}
else
{
int nowlength = mystrlen(string->p);//求出當前長度
int movelength = mystrlen(pos);//求出現在要移動的長度
for (int i = nowlength; i > nowlength - movelength; i--)//移動
{
string->p[i] = string->p[i - 1];//輪詢
}
string->p[nowlength - movelength] = ch;//插入
string->p[nowlength + 1] = '\0';//結尾
}
}
void addstring(mystring *string, char*str, char *pos)//任意增加字符串
{
if (pos == NULL || string == NULL)
{
return;
}
int nowmystringlength = mystrlen(string->p);//獲取當前長度
int addstringlength = mystrlen(str);//要增加的長度
if (nowmystringlength + addstringlength + 1 > string->reallength)//判定是否越界
{
int needaddlength = nowmystringlength + addstringlength + 1 - (string->reallength);
//printf("%d",needaddlength);
string->p = (char *)realloc(string->p, string->reallength + needaddlength);//增加字符串長度
string->reallength += needaddlength;//增加長度
//先移動，再拷貝
int nowlength = mystrlen(string->p);//求出當前長度
int movelength = mystrlen(pos);//求出現在要移動的長度
int insertlength = strlen(str);//要求出插入的長度
for (int i = nowlength; i >= nowlength - movelength; i--)
{
string->p[i + insertlength] = string->p[i];//字符移動
}
for (int j = 0; j < insertlength; j++)
{
string->p[nowlength - movelength + j] = str[j];//賦值拷貝
}
}
else
{
int nowlength = mystrlen(string->p);//求出當前長度
int movelength = mystrlen(pos);//求出現在要移動的長度
int insertlength = strlen(str);//要求出插入的長度
for (int i = nowlength; i >= nowlength - movelength; i--)
{
string->p[i + insertlength] = string->p[i];//字符移動
}
for (int j = 0; j < insertlength; j++)
{
string->p[nowlength - movelength + j] = str[j];//賦值拷貝
}
}
}
void changefirstchar(mystring *string, const char oldchar, const newchar)//改變字符
{
char *pstr = string->p;
while (*pstr != '\0')
{
if (*pstr == oldchar)//查找
{
*pstr = newchar;//賦值
return;
}
pstr++;
}
}
void changefirststring(mystring *string, char * const oldstring, char *const newstring)//改變字符串
{
char *pfind = findfirststring(string, oldstring);//找到位置
if (pfind != NULL)
{
deletefirststring(string, oldstring);//刪除
addstring(string, newstring, pfind);//插入
}
}
3.編寫main.c
#include
#include
#include "mystring.h"
void main()
{
mystring string1;
initwithstring(&string1, "note");
printfstring(&string1);
//backaddchar(&string1, 'd');
backaddstring(&string1, "padnotepadnotepad");
printfstring(&string1);
while (findfirststring(&string1, "notepad"))
{
changefirststring(&string1, "notepad", "123456789");
}
//char *p = findfirstchar(&string1, 't');
//if (p != NULL)
//{
// addstring(&string1,"12345", p);
//}
//deletefirstchar(&string1, 'e');
//deletefirststring(&string1, "pad");
//char *strp = findfirstchar(&string1, 'a');
//*strp = 'A';
/*char *strp = findfirststring(&string1,"ada");
if (strp != NULL)
{
*strp = 'X';
}*/
printfstring(&string1);
//run(&string1);
system("pause");
}
