c++简单实现string类

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#include<iostream>#include<cstring>using namespace std;class mystring{public:    mystring(char *s);    mystring();    ~mystring();//虚构函数用来释放动态内存    void addstring(char *s);//连接两个字符串    void stringup(char *s);//字符串大写换小写    void change(char *s);//改变字符串    void show();//输出字符串private:    int len;    char *p;};mystring::mystring(char *s){    len=strlen(s);    p=new char [len+1];    strcpy(p,s);}mystring::mystring(){    len=0;    p=new char [len+1];}mystring::~mystring(){    delete []p;    len=0;}void mystring::addstring(char *s){    int tlen=strlen(s);    char *temp=new char [len+1];    strcpy(temp,p);        delete []p;    p=new char [len+tlen+1];//p的动态内存重新申请    strcpy(p,temp);    strcat(p,s);    delete temp;//释放临时动态内存}void mystring::stringup(char *s){    int i;    if(p!=NULL)        delete []p;    len=strlen(s);    p=new char [len+1];    strcpy(p,s);    for(i=0;i<len;i++)    {        if(p[i]>='a'&&p[i]<='z')        {            //s[i]=s[i]-32;b不行            p[i]=s[i]-32;        }    }}void mystring::change(char *s){    delete []p;    len=strlen(s);    p=new char [len+1];    strcpy(p,s);}void mystring::show(){    cout<<p<<endl;}void main(){    mystring ms("awdseswsa");    ms.show();    ms.addstring("123");    ms.show();    ms.change("dedede");    ms.show();    ms.stringup("abc");    ms.show();}

原文链接: https://www.cnblogs.com/huhuuu/archive/2011/04/17/2019047.html

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