Question

我需要为课程提供一些编程帮助。我在下面编写了代码，但是我的老师说我在阅读数据文件时需要使用2 for循环。我不知道怎么做...有什么建议吗？

我的代码：

ifstream infile;
infile.open("dive.txt");
for(int i = 0; i <= 6; i++)
    infile >> contestantNames[i][0] >> contestantNames[i][1] >> judgeScores[i][0] >> judgeScores[i][1] >> judgeScores[i][2] >> judgeScores[i][3] >> judgeScores[i][4] >> judgeScores[i][5] >> judgeScores[i][6] >> judgeScores[i][7];
infile.close();

Answer 1

而不是重复写作

infile >> contestantNames[0][0] >> contestantNames[0][1] >> judgeScores[0][0] >> judgeScores[0][1] >> judgeScores[0][2] >> judgeScores[0][3] >> judgeScores[0][4] >> judgeScores[0][5] >> judgeScores[0][6] >> judgeScores[0][7];
infile >> contestantNames[1][0] >> contestantNames[1][1] >> judgeScores[1][0] >> judgeScores[1][1] >> judgeScores[1][2] >> judgeScores[1][3] >> judgeScores[1][4] >> judgeScores[1][5] >> judgeScores[1][6] >> judgeScores[1][7];
infile >> contestantNames[2][0] >> contestantNames[2][1] >> judgeScores[2][0] >> judgeScores[2][1] >> judgeScores[2][2] >> judgeScores[2][3] >> judgeScores[2][4] >> judgeScores[2][5] >> judgeScores[2][6] >> judgeScores[2][7];
infile >> contestantNames[3][0] >> contestantNames[3][1] >> judgeScores[3][0] >> judgeScores[3][1] >> judgeScores[3][2] >> judgeScores[3][3] >> judgeScores[3][4] >> judgeScores[3][5] >> judgeScores[3][6] >> judgeScores[3][7];
infile >> contestantNames[4][0] >> contestantNames[4][1] >> judgeScores[4][0] >> judgeScores[4][1] >> judgeScores[4][2] >> judgeScores[4][3] >> judgeScores[4][4] >> judgeScores[4][5] >> judgeScores[4][6] >> judgeScores[4][7];
infile >> contestantNames[5][0] >> contestantNames[5][1] >> judgeScores[5][0] >> judgeScores[5][1] >> judgeScores[5][2] >> judgeScores[5][3] >> judgeScores[5][4] >> judgeScores[5][5] >> judgeScores[5][6] >> judgeScores[5][7];
infile >> contestantNames[6][0] >> contestantNames[6][1] >> judgeScores[6][0] >> judgeScores[6][1] >> judgeScores[6][2] >> judgeScores[6][3] >> judgeScores[6][4] >> judgeScores[6][5] >> judgeScores[6][6] >> judgeScores[6][7];

你写了一个for循环。

还有什么重复吗？

Answer 2

你的两个for循环将是

for (int i = 0; i <= 6; i++) {
    infile >> contestantNames[i][0] >> contestantNames[i][1];
    for (int j = 0; j <= 7; j++) {
        infile >> judgeScores[i][j];
    }
}

您的教师希望您将连续的judScores简化为for循环，这样更容易阅读。

Answer 3

ifstream infile;
infile.open("dive.txt");

for (int i = 0; i <= 6; i++)
{
  infile >> contestantNames[i][0] >> contestantNames[i][1];

  // The next part is what your teacher was talking about.
  // You wrote judgeScores[i][0] >> judgeScores[i][1] >> ...
  // seven times, which is pretty redundant. Programmers are *extremely* lazy
  // so we loop constantly, wherever possible:

  for (int j = 0; j <= 7; j++)
  {
     infile >> judgeScores[i][j];
  }
}

infile.close();

Answer 4

我认为你的教练意味着在所有参赛者中循环一次，然后再次循环输入每个参赛者的信息（姓名和分数）。

所以尝试这样的事情：

ifstream infile;
infile.open("dive.txt");
for(int i = 0; i <= 6; i++) {
    infile >> contestantNames[i][0] >> contestantNames[i][1];
    for (int j = 0; i <= 7; j++) {
         infile >> judgeScores[i][j];
    }
}
infile.close();

注意：括号不是必需的，因为每个语句都包含一行。但这是规则的例外 - 如果for循环中有多于1个语句，则需要括号。（你可能知道。）

Answer 5

当有两个以上的居民时，你老师可能会要你考虑这个案子。

的内容

nc = 6;  // the number of contenstans
for (int c=0; c<nc; c++) {
  // other for loop here...
}

Answer 6

即使是三个循环也让老师惊喜：

ifstream infile;
infile.open("dive.txt");
for(int i = 0; i <= 6; i++)
{
    for (int j = 0; j < 2; ++j)
    {
        infile >> contestantNames[i][j];
    }

    for (int j = 0; j < 8; ++j)
    {
       infile >> judgeScores[i][j];
    }
}
infile.close();

Answer 7

使用while循环检查文件结尾（EOF），以防有超过6行。坏数据的测试用例也不会受到影响。

将1 C ++循环变为2

7 个答案: