问用于检查平衡()、{}和[]字符串的C++程序

EN

bool ExpressionManager::isBalanced(string expression)
{
//remove whitespace
string edited;
for(int i = 0; i < expression.length(); i++)
{
    if(expression[i] == ' ')
    {
        continue;
    }
    else
    {
        edited += expression[i];
    }
}
expression = edited;

//set up brckets 
string brackets;

for(int i = 0; i < expression.length(); i++)
{
    if (expression.at(i)=='(')
    {
        brackets += expression.at(i);
    }
    if (expression.at(i)=='[')
    {
        brackets += expression.at(i);
    }
    if (expression.at(i)=='{')
    {
        brackets += expression.at(i);
    }
    if (expression.at(i)=='}')
    {
        brackets += expression.at(i);
    }
    if (expression.at(i)==']')
    {
        brackets += expression.at(i);
    }
    if (expression.at(i)==')')
    {
        brackets += expression.at(i);
    }
}

int parenbal = 0;
int brackbal = 0;
int mustachebal = 0;

    for (int i = 0; i<(brackets.size());i++)
    {

        if(brackets[i]=='(')
            parenbal++;
        if(brackets[i]=='[')
            brackbal++;
        if(brackets[i]=='{')
            mustachebal++;

        if(brackets[i]==')')
            parenbal--;
        if(brackets[i]==']')
            brackbal--;
        if(brackets[i]=='}')
            mustachebal--;
    }

    bool isbalanced = false;

    if ((mustachebal==0)&&(brackbal==0)&&(parenbal==0))
    {
        isbalanced = true;
    }

    //check for brackets mixed up with other stuff.


return isbalanced;
}