Day01_C++编程

01.思维导图

02.

方法一：

#include <iostream>
#include <cstring>
#include <iostream>
using namespace std;
class mystring
{
private:char* buf;int len;public:mystring(const char* str);void copy(const char* ptr);void copy(mystring ptr);void append(const char* ptr);void append(mystring ptr);void compare(const char* ptr);void show(){cout << buf << endl;}
};
mystring::mystring(const char* str):len(strlen(str))
{buf=(char*)malloc(len+1);strcpy(buf,str);
}//复制字符串
void mystring::copy(const char* ptr)
{int i=0;len=strlen(ptr);while(ptr[i]!='\0'){buf[i]=ptr[i];i++;}buf[i]='\0';
}void mystring::copy(mystring ptr)
{int i=0;len=ptr.len;while(ptr.buf[i]!='\0'){buf[i]=ptr.buf[i];i++;}buf[i]='\0';
}
//追加字符串
void mystring::append(const char* ptr)
{int i=0,j=0;while(buf[i]!='\0'){i++;};for(;ptr[j]!='\0';j++,i++){buf[i]=ptr[j];}buf[i]='\0'; len=i;
}void mystring::append(mystring ptr)
{int i=len,j=0;while(ptr.buf[j]!='\0'){buf[i]=ptr.buf[j];i++;j++;
}
buf[i]='\0';
len=i;}
//主函数
int main()
{mystring str = "hello";str.show();mystring ptr = "world";str.copy(ptr);str.show();str.copy("你好");str.show();str.append(ptr);str.show();str.append("你好");str.show();
}

方法二：

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>using namespace std;
class mystring{
private://指向一个堆空间,该堆空间用来保存外部传入的字符串char* buf;int len;//记录buf里面保存的字符串有多少
public:mystring(const char* s){len=strlen(s);buf=(char*)malloc(len+1);strcpy(buf,s);}void copy(mystring s){len=s.len;char* str=s.buf;strcpy(buf,str);}void copy(const char* s){len=strlen(s);strcpy(buf,s);}void append(mystring s){len+=s.len;char* str=s.buf;strcat(buf,str);}void append(const char* s){int l=strlen(s);len+=l;strcat(buf,s);}int compare(mystring s){char* str=s.buf;return strcmp(buf,str);}int compare(const char* s){return strcmp(buf,s);}void show(){cout<<buf<<endl;}char at(int n){return buf[n];}};int main(int argc,const char** argv)
{mystring str="hello";//这段代码要求一定为mystring类写一个可隐式调用的单参构造函数mystring ptr="world";//在写单参构造函数的时候,私有成员len使用列表初始化的形式初始化str.copy(ptr);//str.copy("nihao");str.show();str.append(ptr);str.append("你好");str.show();str.compare(ptr);str.compare("您好");str.show();//最后再写一个show函数,用来在终端输出str里面保存的字符串cout<<str.at(2)<<endl;}

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>                        
#include <vector>
#include <memory>using namespace std;
class mystring{
private:char* buf;int len;
public:mystring(){}mystring(const char* r);void copy(mystring r);//此功能其实就是buf的set接口,即setBufbool compare(mystring r);void append(mystring r);char at(int index);void show();
};mystring::mystring(const char* r):len(strlen(r)),buf((char*)calloc(1,len+1))
{//len=strlen(r);//buf=(char*)calloc(1,len+1);strncpy(buf,r,len);
}void mystring::copy(mystring r)
{//如果len>=r.len直接用//如果len<r.len,根据r.len申请新空间,释放原先空间if(len<r.len){len=r.len;free(buf);buf=(char*)calloc(1,len+1);}strncpy(buf,r.buf,len);
}bool mystring::compare(mystring r)
{/*if(strcmp(buf,r.buf)==0){return true;}else{return false;}*/return strcmp(buf,r.buf)==0;
}void mystring::append(mystring r)
{len=len+r.len;char* temp=buf;buf=(char*)calloc(1,len+1);strcpy(buf,temp);strcat(buf,r.buf);
}char mystring::at(int index)
{return buf[index];
}void mystring::show()
{cout<<buf<<endl;
}int main(int argc, const char** argv)
{mystring str="hello";mystring ptr="world";str.show();ptr.show();str.copy(ptr);str.show();str.copy("niho");str.show();cout<<(str.compare(ptr))<<endl;cout<<(str.compare("world"))<<endl;str.append(ptr);str.show();str.append("world");str.show();cout<<str.at(0)<<endl;return 0;                             
}