构造函数错误，在崩溃之前打印出'a'然后打印三角形

Question

    QuBiEngine::QuBiEngine(ifstream& dnaFile)
{
    int i = 0;
    while(!dnaFile.eof()) //while the file isn't at its end
    {
        dna.push_back(""); //creates an element
        if(!dnaFile.good())//checks for failbits and other errors
        {
            dna[i] = "Not a valid sequence";
            i++;
            continue; 
        }
        getline(dnaFile, dna[i]);
        //checks to see if the character is valid ie: a, t, c, g
        for(int j=0; j<dna[i].length(); j++)
        {
            dna[i][j] = putchar(tolower(dna[i][j]));
            if((dna[i][j]!='a')||(dna[i][j]!='t')||(dna[i][j]!='c')||(dna[i][j]!='g'))
            {
                dna[i] = "Not a valid sequence";
                i++;
                break;
            }            
        }
        i++;        
    }
}

这将获取dnaFile ifstream中的每一行，如果它通过了测试，则将其放入向量中，如果没有，则只将无效的东西放入向量中。

Answer 1

我想通了，第二个if语句中的i++使它增加了两次，从而溢出了我的向量。

Answer 2

您可能在标记的地方遗漏了break;：

    QuBiEngine::QuBiEngine(ifstream& dnaFile)
{
    int i = 0;
    while(!dnaFile.eof()) //while the file isn't at its end
    {
        dna.push_back(""); //creates an element
        if(!dnaFile.good())//checks for failbits and other errors
        {
            dna[i] = "Not a valid sequence";
            i++;
            continue; 
        }
        getline(dnaFile, dna[i]);
        bool bad = false;
        //checks to see if the character is valid ie: a, t, c, g
        for(int j=0; j<dna[i].length(); j++)
        {
            dna[i][j] = putchar(tolower(dna[i][j]));
            if((dna[i][j]!='a')||(dna[i][j]!='t')||(dna[i][j]!='c')||(dna[i][j]!='g'))
            {
                dna[i] = "Not a valid sequence";
                break;
            }            
        }
        i++;   
    }
}

除此之外：dna变量是什么？你能告诉我们任何声明和初始化吗？

除此之外，如果你的dna被宣布为不会超出界限（没有检查）