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我似乎陷入了代码中某处的无限循环，但我找不到在哪里。我正在为一门课做作业，要求我平均两组学生（2 个输入文件）的分数并将结果输出到 results.out。我被困在某个地方，需要知道下一步该往哪里看。我已经复制了我的代码和下面的两个输入文件。截至目前，我的 results.out 文件中没有任何内容。

我的代码：

#include <iostream>
#include <fstream>
using namespace std;

int main()    
{
    char courseID1;     //Course Letter
    char courseID2;
    int count = 1,
        sum = 0,
        sum2 = 0,
        k = 0,
        score;
    ifstream group1;    //Input stream for group1
    ifstream group2;    //Input stream for group2
    ofstream results;   //Output stream for the results

    //Open the input files
    group1.open("group1.dat");
    group2.open("group2.dat");

    //Open the output file
    results.open("results.out");

    while (count <= 5)
    {
        //Read the class ID
        group1 >> courseID1;
        group2 >> courseID2;
        sum = 0;
        k = 0;

        group1 >> score;
        while(score != -999)
        {
            k = k + 1;
            sum = sum + score;
        }

        float avg1 = (float)sum/k;
        k = 0;
        sum2 = 0;
        score = 0;
        group2 >> score;
        while (score != -999)
        {
            k = k + 1;
            sum = sum + score;
        }

        float avg2 = (float)sum2/k;

        results << "CourseID\tGroup No.\tCourse Average" << endl << endl;
        results << courseID1 << "\t1" << avg1;
        results << "\t\t2" << avg2 << endl << endl;

        count++;
    }

return 0;
} //end of main

组1.dat

A 80 100 50 10 32 90 89 100 23 50 -999
B 80 90 80 94 90 34 23 63 23 80 90 -999
C 10 30 20 10 90 50 89 23 90 68 90 10 60 90 73 35 90 -999
D 34 80 45 89 90 n23 90 12 34 90 84 100 90 59 -999
E 100 83 93 20 63 -999

组2.dat

A 20 75 40 25 80 89 100 60 -999
B 80 50 70 19 10 18 80 90 90 26 -999
C 100 30 20 40 90 50 18 90 90 45 90 80 70 30 35 40 -999
D 80 85 45 92 10 90 24 90 23 65 72 90 34 100 -999
E 95 100 88 98 69 -999

以下是输出的样子：

courseID Group No. Course Average
    A          1        80.50
               2        82.75

    B          1        78.00
               2        75.35

编辑：

在将 while 循环更改为之后，我现在得到了这个结果

while( (group >> score) && score != -999)

我的 result.out 看起来像这样：

CourseID    Group No.   Course Average

A   162.4       20

CourseID    Group No.   Course Average

B   167.9091        20

CourseID    Group No.   Course Average

C   154.5882        20

CourseID    Group No.   Course Average

D   167.6       20

CourseID    Group No.   Course Average

D   1-NaN       20

我该如何解决？

4

4 回答 4

1

您的 while 语句：

while (score != -999){
    k = k + 1;
    sum = sum + score;
}

你永远不会修改'score'的值，从而创建一个无限循环。

于 2013-10-18T17:01:48.500 回答
0 
while (score != -999)
    {
        k = k + 1;
        sum = sum + score;
    }

你陷入了这个循环。score == -999仅当您不修改score此循环中任何位置的值时，循环才会退出。

始终使用调试器。你会很快找到你的程序卡住的地方。

于 2013-10-18T17:02:05.733 回答
0

您应该group1 >> score在结束括号之前添加到循环内。像这样的东西：

group1 >> score;
while(score != -999)
{
    k = k + 1;
    sum = sum + score;
    group1 >> score;
}

第二个循环也一样

这看起来更好：

while( (group >> score) && score != -999 )
{
    k = k + 1;
    sum = sum + score;
}
于 2013-10-18T17:02:16.680 回答
0

我想，像这样：

do
{
    group1 >> score;
    k = k + 1;
    sum = sum + score;
} while (score != -999);
于 2013-10-18T17:05:25.907 回答