作者franklin1997 (柴柴可愛)
看板C_and_CPP
標題[問題]編譯完出現 undefined reference to
時間Fri Mar 31 04:29:28 2017
開發平台(Platform): (Ex: Win10, Linux, ...)
linux
編譯器(Ex: GCC, clang, VC++...)+目標環境(跟開發平台不同的話需列出)
額外使用到的函數庫(Library Used): (Ex: OpenGL, ...)
問題(Question)：
大家好，剛接觸C++沒多久(以前學c),還不太熟悉請多指教。
編譯完後出現一群undefined reference to，
我覺得應該是在講class R的問題，可是檢查了R找不出錯在哪...
詳細狀況如下:
/tmp/ccY2jGY2.o: In function `R::R(int, int)':
test.cpp:(.text._ZN1RC2Eii[_ZN1RC5Eii]+0x13): undefined reference to `R::r1'
test.cpp:(.text._ZN1RC2Eii[_ZN1RC5Eii]+0x1c): undefined reference to `R::r2'
/tmp/ccY2jGY2.o: In function `R::now()':
test.cpp:(.text._ZN1R3nowEv[_ZN1R3nowEv]+0x10): undefined reference to `R::r1'
/tmp/ccY2jGY2.o: In function `R::Ans(float)':
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x68): undefined reference to `R::s'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x6e): undefined reference to `R::r1'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x7f): undefined reference to `R::s'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x90): undefined reference to `R::r2'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x96): undefined reference to `R::r1'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0xff): undefined reference to `R::r1'
test.cpp:(.text._ZN1R3AnsEf[_ZN1R3AnsEf]+0x105): undefined reference to
`R::r1'
collect2: error: ld returned 1 exit status
餵入的資料(Input)：
預期的正確結果(Expected Output)：
錯誤結果(Wrong Output)：
程式碼(Code)：(請善用置底文網頁, 記得排版)
codePad:
https://codepad.remoteinterview.io/HUAVHCNAJT
#include <iostream>
#include <cmath>
#include <cstdlib>
# include <iostream>
# include <string>
# include <fstream>
using namespace std;
//專門拿來算R的class
class R{
public:
int ans;//所求
R(){
cerr<<"no data to calculate";
}
R(int r1_,int r2_){
r1=r1_;
r2=r2_;
} //還沒有輸入s值的R值
int now(){
ans=r1;
return ans;
} //有輸入s的R值
int Ans(float s_){
//s 只有三種:1 ,0 ,0.5
if (s_==1||s_==0||s_==0.5){
s=s_;
}
else{
cerr<<"need to be 1 0.5 0";
exit(1);
}
r1=r1+k*(s-(1/(1+pow(10,(r2 - r1/400))))); //R的計算公式
ans=r1;
return ans;
}
private:
static int r1,r2;
static float s;
static const int k=32;
};
int main(){
ofstream outFile("filein.txt",ios::out);//先做一個filein.txt
if(!outFile) {
cerr<<"err\n";
exit(1);
}
//輸入原始數據
outFile << "k\tr1\tr2\n";
outFile << 32<<"\t"<<1613<<"\t"<<1609<<endl;
outFile << "sa\tsb\n";
outFile << 0 <<"\t"<< (1-0)<<"\t"<<endl;
outFile << 0.5 <<"\t"<< (1-0.5)<<"\t"<<endl;
outFile << 0.5 <<"\t"<< (1-0.5)<<"\t"<<endl;
outFile << 0 <<"\t"<< (1-0)<<"\t"<<endl;
outFile << 0 <<"\t"<< (1-0)<<"\t"<<endl;
outFile << 0 <<"\t"<< (1-0)<<"\t"<<endl;
outFile.close();
//接下來要開始讀filein,txt，然後寫一個fileout.txt
//宣告，等一下會用到
string headline1, headline2;
int r1,r2,k;
float pointa,pointb;//s值
ifstream inFile("filein.txt",ios::in);
ofstream ouFile("fileout.txt",ios::out);
//成功?
if(!inFile){
cerr<<"filein.txt fail";
exit(1);
}
if(!ouFile){
cerr<<"fileout.txt fail";
exit(1);
}
//開始讀檔
getline(inFile,headline1);
inFile>>k>>r1>>r2;
R ra(r1,r2); //初始化ra
R rb(r2,r1); //初始化rb
ouFile<< ra.now()<<"\t"<< rb.now()<<"\n"; //ra rb原封不動寫入fileout.txt
//開始讀s值
while(inFile>>pointa>>pointb){
ouFile<< ra.Ans(pointa)<<"\t"<< rb.Ans(pointb)<<"\n"; //算一算寫入fileout.txt//
}
inFile.close();
ouFile.close();
}
補充說明(Supplement)：*[m
這裡的R是在算Elo rate。
s是指每次勝負的得分。贏者得一分，輸了零分，平手0.
5
研究了很久都不了，拜託幫忙了
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※ 編輯: franklin1997 (218.164.190.214), 03/31/2017 04:34:08
※ 編輯: franklin1997 (218.164.190.214), 03/31/2017 04:34:49
1F：推 steve1012: 你需要 init static data member 吧 03/31 04:37
2F：→ steve1012: 找個地方初始化你class 的r1 03/31 04:38
3F：推 steve1012: 話說static 真的是你要的嗎 03/31 04:39
呃 應該是不用沒錯(打程式的時候自己混亂了
我睡一下再改改看
甘溫
※ 編輯: franklin1997 (36.238.194.129), 03/31/2017 05:00:50
4F：推 loveflames: 問題有夠明顯，static data member寫在類裡面只是聲 03/31 07:30
5F：→ loveflames: 明，非定義 03/31 07:30
我把那兩個static刪掉了，謝謝兩位大大
※ 編輯: franklin1997 (36.238.194.129), 03/31/2017 11:28:37
6F：推 HMKRL: 難怪我覺得這問題好眼熟XDD 這是算elo的對吧XDD 04/07 03:00