剑指Offer之面试题4：替换空格

所有代码均通过G++编译器测试，仅为练手纪录。

//面试题4：替换空格

//题目：请实现一个函数，把字符串中的每个空格替换成“％20”.

//    例如输入“We are happy.”,则输出“We％20are％20happy.”

//面试题4：替换空格
//题目：请实现一个函数，把字符串中的每个空格替换成“％20”.
//     例如输入“We are happy.”,则输出“We％20are％20happy.”
void Replace(string& strBuff,char cSrc,const string& strDst)
{
    
    const char *pBuff = strBuff.c_str();
    unsigned long nBuffSize = strBuff.size();
    
    int nSrcCount = 0;
    while (nBuffSize--)
    {
        if(cSrc == pBuff[nBuffSize])
        {
            ++nSrcCount;
        }
    }
    
    if(nSrcCount > 0)
    {
        nBuffSize = strBuff.size();
        unsigned long nNewBuffSize = nBuffSize + (strDst.size()-1)*nSrcCount;
        strBuff.resize(nNewBuffSize);
        
        char *p = const_cast<char *>(strBuff.c_str());
        
        const char *pDst = strDst.c_str();
        unsigned long nDstSize = strDst.size();
        
        --nNewBuffSize;
        while(nBuffSize--)
        {
            if(cSrc == p[nBuffSize])
            {
                unsigned long nDstIndex = nDstSize - 1;
                
                while(nDstIndex+1)
                {
                    p[nNewBuffSize--] = pDst[nDstIndex--];
                }
            }
            else
            {
                p[nNewBuffSize--] = p[nBuffSize];
                
            }
            
        }
    }
}

void TestReplace()
{
    string strBuff = " We are happy.   ";
    Replace(strBuff, ' ',"%20");
    LogInfo("strBuff:%s",strBuff.c_str());
}

ZhaiPillary

2016-12-23