[英]Assign std::vector address of another std::vector
我正在写一个平衡化学方程式的程序。 该程序通过取等式字符串,根据等号将其分成大小为2的std :: vector进行工作,然后将左侧的splitEquation separatedEquation[0]
和右侧的separatedEquation[1]
解析为另一组std :: vector的leftHalf和rightHalf分别。
问题
我有一个函数方程:: filterEquation分析给separatedEquation
的元素名称。 我想使用一个临时向量,该向量指向leftHalf或rightHalf的地址。 我知道这可能令人困惑,但这是我的代码以及我要尝试做的事情。 我想我需要使用指针,但是我以前从未使用过指针,并且效率不高。
void Equation::filterEquation()
{
for(int i=0; i<separatedEquation.size(); i++) //i = index of separated equation
{
int index=0;
std::vector<std::string> equationHalf;
if(i==0)
equationHalf = leftHalf; //set equationHalf to the address of leftHalf
if(i==1)
equationHalf = rightHalf; //set equationHalf to the address of rightHalf
for (std::string::iterator it = separatedEquation[i].begin(); it!=separatedEquation[i].end(); ++it, index++)
{
//Elements are set up so that He = Helium, while H = Hydrogen. This separates the elements based upon upper and lowercae
bool UPPER_LETTER = isupper(separatedEquation[i][index]); //true if character is upperCase
bool NEXT_LOWER_LETTER = islower(separatedEquation[i][index+1]); //true if next is lowerCase
if (UPPER_LETTER)// if the character is an uppercase letter
{
if (NEXT_LOWER_LETTER)
{
std::string temp = separatedEquation[i].substr(index, 2);//add THIS capital and next lowercase
equationHalf.push_back(temp); // add temp to vector
}
else if (UPPER_LETTER && !NEXT_LOWER_LETTER) //used to try and prevent number from getting in
{
std::string temp = separatedEquation[i].substr(index, i);
equationHalf.push_back(temp);
}
}
}
}
}
一般而言,您将替换为:
std::vector<std::string> equationHalf;
...
equationHalf = leftHalf // same for rightHalf
同
std::vector<std::string>* equationHalf;
...
equationHalf = &leftHalf // same for rightHalf
然后替换equationHalf.
Half的任何实例equationHalf.
与equationHalf->
。
但是,在您的情况下,我可能会考虑重新考虑您的设计,例如将对equationHalf
进行运算的代码分解为一个函数,并将其传递给要对vector
进行操作的引用,例如void doStuff(std::vector<std::string> & equationHalf)
,然后只需调用doStuff(leftHalf)
和doStuff(rightHalf)
。
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