字符串类的创建（下）

Posted 2022-02-06 为了财务自由！

//非const就用&，因为可以出现在赋值号左边
char& String::operator[] (int i)

    if((0<=i) && (i<m_length))
    
        return m_str[i];
    
    else
    
        THROW_EXCEPTION(IndexOutOfBoundsException,"Parameter i is invalid...\\n");
    

char String::operator[] (int i)const

    return (const_cast<String&>(*this))[i];

bool String::equal(const char* l,const char* r,int len)const

    bool ret = true;
    for(int i=0;i<len && ret;i++)
    
        ret = ret && (l[i] == r[i]);
    
    return ret;


bool String::startWith(const char* s)const

    bool ret = (s != NULL);
    if(ret)
    
        int len = strlen(s);
        ret = (len < m_length) && equal(m_str,s,len);
    
    return ret;

bool String::startWith(const String& s)const

    return startWith(s.m_str);

bool String::endOf(const char* s)const

    bool ret = (s != NULL);
    if(ret)
    
        int len = strlen(s);
        char* str = m_str + (m_length-len);
        ret = (len < m_length) && equal(str,s,len);
    
    return ret;

bool String::endOf(const String& s)const

    return endOf(s.m_str);

String& String::insert(int i,const char* s)

    if((0<=i) && (i<=m_length))
    
        if((s != NULL) && (s[0]!='\\0'))
        
            int len = strlen(s);
            char* str = reinterpret_cast<char*>(malloc(m_length+len+1));
            if(str != NULL)
            
                strncpy(str,m_str,i);
                strncpy(str+i,s,len);
                strncpy(str+i+len,m_str+i,m_length-i);
                str[m_length+len]='\\0';
                free(m_str);
                m_str=str;
                m_length=m_length+len;
            
            else
            
                THROW_EXCEPTION(NoEnoughMemoryException,"No memory to insert string value...\\n");
            
        
    
    else
    
        THROW_EXCEPTION(IndexOutOfBoundsException,"Parameter i is invalid...\\n");
    
    return *this;

String& String::insert(int i,const String& s)

    return insert(i,s.m_str);

String& String::trim()

    int b=0;
    int e=m_length-1;

    while(m_str[b] == ' ')b++;
    while(m_str[e] == ' ')e--;

    if(b == 0)//前面没空格
    
        m_str[e+1] = '\\0';
        m_length = e+1;
    
    else
    
        for(int i=0,j=b;j<=e;i++,j++)
        
            m_str[i] = m_str[j];
        
        m_str[e-b+1] = '\\0';
        m_length=e-b+1;
    

    return *this;