• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>

            The Way of C++

              C++博客 :: 首頁 :: 聯系 :: 聚合  :: 管理
              55 Posts :: 0 Stories :: 19 Comments :: 0 Trackbacks

            公告

            The first time i use this blog, i will write something that i learn which i think is worth write down.

            常用鏈接

            留言簿(3)

            我參與的團隊

            搜索

            •  

            最新評論

            閱讀排行榜

            評論排行榜

                Forgive my ugly English description ,and i may it will help you. -_-
                (Reference by : http://www.cplusplus.com/reference/iostream/istream/getline.html)
                the function prototype is as follows:
                istream& getline (char* s, streamsize n );
                istream& getline (char* s, streamsize n, char delim );
                
                the function extracts charatcters from the input sequence and stores them as c-tring into the array begin at s. Characters are extracted until either n-1 characters have been extracted or the delimiting character is found.( the char delim can be specified by yourself, or be '\n' by default). Remember this, when the delimiter is found ,it will be extracted and discarded, i.e, it is extracted from the input stream and not stored to the s , and the next input operation will begin after this extracted delimiter. ). After the data extracted ,the ending null charactor ('\0') will be appended to s automatically.
                The following is same examples.
                
             1 #include<iostream>
             2 using namespace std;
             3 int main()
             4 {
             5     char fruit[100];
             6     cin.getline(fruit,100,'*');
             7     cout<<fruit<<endl;
             8     
             9     system("pause");
            10 }
            11 
                
                now ,when you input "banana apple pear\n"( here \n means the enter), then the console will show "banana apple pear"
               
               also ,you can specify the delimiter by yourself  as this.
              
             1 #include<iostream>
             2 using namespace std;
             3 int main()
             4 {
             5     char fruit[100];
             6     cin.getline(fruit,100,'*');
             7     cout<<fruit<<endl;
             8     
             9     system("pause");
            10 }
            11 
                now,when you input "banana apple pear * orange\n",then the console will show " banana apple pera" , here the orange is not readed because is is after the delimiter '*'.
                
                So simple about use this function ,right ? now see this example .
                
             1 #include<iostream>
             2 using namespace std;
             3 int main()
             4 {
             5     char fruit[100];
             6     while(cin.getline(fruit,100,'*'))
             7     {
             8         cout<<fruit<<endl;
             9     }
            10     
            11     system("pause");
            12 }
            13 
              Here we want to input number of lines ,each of line is delimited by a '*'.
              In the first time : we input " banana apple *\n" then the console show "banana apple" ,this is right.
              But the problem comes, in the second input " pear orange *\n", now the console show "\n(\n means a blank line) pear orange". Here a blank line will be output, betray to our will that showing "pear orange";
               The problem is that a '\n' is stored in the fruit in the second time as the first element, i.e, the fruit is "\npear orange\0" in the second input. In the first getline ,it extracted the input stream until the first '*' was found, then it discarded the '*', but the following character is '\n' which you input in the first time, this '\n' is still in the input stream. And the second getline read the stream form this '\n'. As we know ,the delimiter is specified as '*' ,so the '\n' is not a delimiter here ,and it will be stored into the second fruit. 
               How to resovle this problem ? In order to avoid the situation above ,we can use the get to extract the '\n' character. And now it work normally.
              
             1 #include<iostream>
             2 using namespace std;
             3 int main()
             4 {
             5     char fruit[100];
             6     while(cin.getline(fruit,100,'*'))
             7     {
             8         cin.get();
             9         cout<<fruit<<endl;
            10     }
            11     
            12     system("pause");
            13 }
            14 
               
               One thing you have to remember is that this is a function of the cin.
               there is also a global function getline() in the heder <string>. But you must use string object as parameter instead of c-string.  See the following example. 
               (Reference to :http://www.cplusplus.com/reference/string/getline.html)
              
             1 #include<iostream>
             2 #include<string>
             3 using namespace std;
             4 int main()
             5 {
             6     string s;
             7     getline(cin,s,'*');
             8     cout<<s<<endl;
             9     system("pause");
            10 }
            11 
                As you can see, the first parameter is istream object on which the extraction operation is performed. The second parameter str is the string object where the extracted content is stored. The Third parameter delim is the delimiting character. The operation of extracting succesive characters is stopped when this delimeter is read. And it will be etracted and discarded. 
               
               
              
              


               
                
                
              
            posted on 2007-12-26 17:55 koson 閱讀(1063) 評論(3)  編輯 收藏 引用 所屬分類: C/C++

            Feedback

            # re: About the use of getline() 2007-12-27 12:21 夢在天涯
            good , where are you in ?
            your english is good!
              回復  更多評論
              

            # re: About the use of getline()[未登錄] 2007-12-27 12:28 Koson
            thx, i'm in guangzhou. Actually, i write this using the reference of the website. But i think this may be a way to improve the written english , despite the content is as simple as that. -_-  回復  更多評論
              

            # re: About the use of getline()[未登錄] 2007-12-27 14:00 jarod
            ..... where are u in ?..................

            should be

            where are u..........  回復  更多評論
              

            亚洲色大成网站WWW久久九九| 国产精品青草久久久久婷婷| 亚洲午夜久久久精品影院 | 国产精品久久永久免费| 91精品国产91热久久久久福利| 久久av免费天堂小草播放| 久久久久99这里有精品10| 久久人人爽人人爽人人AV东京热| 久久夜色tv网站| 国内精品伊人久久久久777| 久久夜色tv网站| 精品久久亚洲中文无码| 97精品国产91久久久久久| 综合久久一区二区三区| 国产成人综合久久精品尤物| 亚洲精品乱码久久久久久蜜桃不卡 | 亚洲人成电影网站久久| 久久久综合九色合综国产| 影音先锋女人AV鲁色资源网久久 | 亚洲色大成网站www久久九| 久久精品无码免费不卡| 99精品国产在热久久无毒不卡 | 国产精品一区二区久久精品| 久久国语露脸国产精品电影| 国产无套内射久久久国产| 99久久这里只有精品| 色婷婷综合久久久久中文| 国产精品99久久久精品无码 | 久久精品国产乱子伦| 国产巨作麻豆欧美亚洲综合久久| 99久久国产综合精品麻豆| 99久久国产精品免费一区二区| 无码人妻久久一区二区三区蜜桃| 亚洲综合婷婷久久| 91亚洲国产成人久久精品| 久久精品国产91久久麻豆自制| 久久ww精品w免费人成| 久久精品国产清高在天天线| 久久精品人人做人人爽97| 久久精品国产亚洲av水果派| 999久久久免费精品国产|