Re: [問題] 如何讓vector<A> Get()得到的資料不可修改
※ 引述《HeyScng ( )》之銘言:
: 3. 如果傳回值是double**,如何使傳回的referene為const,
: 我寫const double** GetInfo, compiler不讓我過耶
double ** 是決不可轉成 const double ** 的,理由如下
double *pd;
const double **ppcd = &pd; //if we can convert double ** to const double **
const double cd = 1.0;
const double * pcd = &cd; //then we can assign a const double * to double *
// by dereference the const double **
*ppcd = pcd; //note: *ppcd is const double*,
// which actually a reference to a double* (pd). //now pd points to a const double.
*pd = 2.0; //oops.
======================================
所以你需要多加個const,返回 const double * const * 即可。
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