至少有一处明显错误

送交者: ak70 于 2010-09-09, 04:54:33:

回答: 请教一个C++问题由 qtl 于 2010-09-09, 04:34:00:

for(int i=0; i<n; ++i) v=c;
v是double指针，而c是double. 你是不是想要*v=c?
另外有一处我不太确定，
xVec(int a):n(a),v(new double[n]){}
C++的标准里有没有明确规定变量初始化的顺序？如果是从左到右还无所谓，如果是从右到左就麻烦了。另外我记不清了，当初始化语句执行的时候，构造函数应该还没有被调用吧？那变量a的值有没有被传递过来？

所有跟贴:

C++ standard does not define the sequence of initialization. (无内容) - steven (0 bytes) 2010-09-09, 10:46:55 (484825)
forgot - qtl (14 bytes) 2010-09-09, 08:24:28 (484735)
Your second suggestion is right. - qtl (24 bytes) 2010-09-09, 08:22:05 (484731)
that is v[i]=c, [i] is eaten by this forum. (无内容) - qtl (0 bytes) 2010-09-09, 05:04:19 (484697)
- then what is dasum() ? (无内容) - ak70 (0 bytes) 2010-09-09, 05:08:30 (484698)
  - also, if i use v[] directly, no error happens - qtl (50 bytes) 2010-09-09, 05:18:02 (484700)
    - I don't quite understand the docs, but - ak70 (450 bytes) 2010-09-09, 05:25:58 (484702)
      - yes, to call fortran with c/c++ - qtl (45 bytes) 2010-09-09, 05:30:27 (484703)
        
        then maybe you should try &v instead of v. (无内容) - ak70 (0 bytes) 2010-09-09, 05:36:21 (484704)
        
        v is the initial address already for the vector (无内容) - qtl (0 bytes) 2010-09-09, 05:44:33 (484705)
        
        yes, but maybe you should try to use the pointer to pointers - ak70 (82 bytes) 2010-09-09, 05:49:23 (484706)
        
        your this suggestion is wrong anyway - qtl (40 bytes) 2010-09-09, 05:51:39 (484707)
        
        if use &v, then **v will be passed - qtl (25 bytes) 2010-09-09, 06:01:24 (484710)
        
        what was the problem? (无内容) - ak70 (0 bytes) 2010-09-09, 05:59:29 (484709)
  - See attached mkl reference - qtl (1992 bytes) 2010-09-09, 05:14:57 (484699)

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