c - 使用scanf在c中的单行上输入多个 double 和不使用数组的循环

Question

我的程序应该读取多个输入并显示最小值、最大值、总和和平均值。它应该看起来像这样:

输入:

2.5 5 3.5 4.5 jfkjk

输出:

min is 2.5
max is 5
sum is 15.5
average is 3.875

程序应该在到达非数字或换行符时退出。用户可以输入任意数量的数字。我不能使用数组，必须使用循环。这就是我的程序的样子:

void numbers()
      {
      double digit;
      double sum = 0;
      double avg = 0;
      double max;
      double min;
      unsigned count = 0;
      //int c;
      max = 0;
      printf("Input:");

      do {
          scanf("%lf", &digit);

          min = digit;
          if(max < digit)
              digit = max;
          if(min < digit)
              digit = min;
          sum += digit;
          count++;
          avg = sum/count;
      } while( scanf("%lf", &digit)==1 )

      printf(" min is %lf max is %lf sum is %lf avg is %lf count is %u", min, max, sum, avg, count);
      }

打印输出:

Input:2.2 2.3 5 3.5 blah 
 min is 3.500000 max is 0.000000 sum is 0.000000 avg is 0.000000 count is 4

Answer 1

您的代码中隐藏着 2 个非常令人不快的错误:

• 迭代数字时更新(不)更新min和max的方式

  这个:

  if(max < digit)
       digit = max;
  if(min < digit)            // <-- the comparison for min is incorrect as well
       digit = min;
  

  应该是:

  if(max < digit)
      max = digit;
  if(min > digit)         
      min = digit;
  

  因为您要更新 min/max，而不是已读取的 digit。

• 循环逻辑

  这个:

  do {
      scanf("%lf", &digit);
      ...
  } while( scanf("%lf", &digit)==1 )
  

  应该是:

  while( scanf("%lf", &digit)==1 ) {
      ...
  }