Question

我需要帮助才能找到问题计算器的问题。该程序在用户插入其字母等级时起作用，例如＆＃34; A或＆＃34;输出是4.0。但我遇到问题的问题是当用户插入＆＃34; A +或A - ＆＃34; ＆＃34; +或 - 添加一个0.3或-0.3到他们的字母等级＆＃34;它不会增加PLus或减号的值。

这就是我所拥有的：

const double Plus = 0.3;
const double Minus = 0.3;



/**
 * Letter grades are A, B, C, D, and F, possibly followed by + or –. 
 * Their numeric values are 4, 3, 2, 1, and 0. In our scheme, there is no F+ or F–, 
 * or A+. Adding a + to the grade increases the numeric value by 0.3, a – decreases it 
 * by 0.3.
 *
 * Input: The letter of Grade with + or -.
 * Output: The value of inserted grade.
 *
 * @param cin the standard input stream.
 * @param cout the standard output stream.
 * @return 0 for success.
 */
int run(istream& cin, ostream& cout)
{
    // Enter your letter grade: C+
    //Grade value is[2.3]
    char list [26] = { "A, B, C, D, F, a, b, c, f" };
    char grade;
    double value;

    cout << "Enter your letter grade: ";
    cin >> grade;

    cout << fixed << setprecision(1);

    if ((grade == 'A' || grade == 'a')){
        value = 4.0;
    }
    else if ((grade == 'A+') || (grade == 'a+')){
        value = 4.0 + 0.3;
    }
    else if (grade == 'A-' || grade == 'a-'){
        value = (4.0 - Minus);
    }
    else if (grade == 'B' || grade == 'b'){
        value = 3.0;
        if (grade == 'B+' || grade == 'b+'){
            value = (3.0 + Plus);
        }
        else if (grade == 'B-' || grade == 'b-'){
            value = (3.0 - Minus);
        }
    }
    else if (grade == 'C' || grade == 'c'){
        value = 2.0;
        if (grade == 'C+' || grade == 'c+'){
            value = (2.0 + Plus);
        }
        else if (grade == 'C-' || grade == 'c-'){
            value = (2.0 - Minus);
        }
    }
    else if (grade == 'D' || grade == 'd'){
        value = 1.0;
        if (grade == 'D+' || grade == 'd+'){
            value = (1.0 + Plus);
        }
        else if (grade == 'D-' || grade == 'd-'){
            value = (1.0 - Minus);
        }
    }
    else if (grade == 'F' || grade == 'f'){
        value = 0.0;
        if (grade == 'F+' || grade == 'f+'){
            value = (0.0 + Plus);
        }
        else if (grade == 'F-' || grade == 'f-'){
            value = (0.0 - Minus);
        }
    }
    else if (!(grade == list[26])){
        cout << "INVALID LETTER GRADE" << endl;
        value = 0;
    }

    cout << "Grade value is [" << value << "]" << endl;


    return 0;
}

Answer 1

简化：

您的问题是成绩是char，无法存储'A+'（2个字符：＆＃39; A＆＃39;，＆＃39; +＆＃39;）。将char grade更改为std::string grade（请记住包含<string>），它应该可以正常工作。

Answer 2

问题是A+或A-是两个字符，因此无法存储在单个char变量中。您可以使用两个变量（尽管如果您没有输入+或-，这可能会有问题，因为没有任何内容可以存储在第二个变量中）或者使用{{ 1}}存储输入的内容，然后检查其中是否有std::string或+。

此外，作为所有-语句的简化，您可以使用switch-case块，或使用此技巧直接从字母等级获得成绩点。

对于大写字母：if

对于小写字母：gradePoint = 4.0 - (letter - 'A')

请注意，由于gradePoint = 4.0 - (letter - 'a')被跳过评分，您必须单独检查和F。

C ++成绩计算器问题

2 个答案: