Question

我似乎在我的代码中的某个地方陷入无限循环，但我找不到位置。我正在为一个班级做一个作业，要求我平均得分2组学生（2个输入文件）并将结果输出到results.out。我被困在某个地方，需要知道我应该在哪里看下一步。我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

group1.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

group2.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

以下是输出结果：

courseID Group No. Course Average
    A          1        80.50
               2        82.75

    B          1        78.00
               2        75.35

编辑：

我现在在将while循环更改为

后得到此结果

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

我该如何解决这个问题？

Answer 1

你的声明：

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

你永远不会修改'得分'的值，从而创造一个无限循环。

Answer 2

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

你陷入了这个循环。该循环仅在score == -999时退出，并且您不会在此循环中的任何位置修改score的值。

始终使用调试器。您很快就会找到程序卡住的位置。

Answer 3

您应该在关闭括号之前在循环内添加group1 >> score。像这样：

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

第二个循环

也是如此

这看起来更好：

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

Answer 4

我想，就像这样：

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

来自c ++中2个输入文件的平均数据停留在循环中

4 个答案: