1

我正在为我的 C++ 课做作业。在这个作业中，我需要编写一个程序，它从 cin 读取数字然后对它们求和，当使用 while 循环输入 0 时停止。

我已经编写了代码并得到了我需要的结果。但是，我陷入了一个持续重新打印结果的 while 循环中。任何人都可以在打印一次结果后给我一些建议来结束这个循环吗？

这是我的代码：

int main ()
{
int i(1), sum(0);
int sum2(0);
const int max(10);

cout << "Enter numbers, one per line. Enter 0 to end:" << endl;

while (i!=0)
{
    cin >> i; 
    sum += i; //add current value of i to sum
    sum2 += 1;
}
while (i==0)
{   
    if (sum < 100) // If total is less than 100
        cout << "Thank you. The total was " << sum << endl 
                 << "The total number of inputs reads: " << sum2 << endl
                 << "The total is less than 100." << endl ;
    else // Else total is greater than 100
            cout << "Thank you. The total was " << sum << endl 
                 << "The total number of inputs reads: " << sum2 << endl 
                 << "The total is greater than 100." << endl ;
}
} //End of Int Main

希望结果没问题。抱歉，我不确定如何在每行上发布数字。我还尝试将 while (i==0) 更改为 if 语句 if (i==0) 但这会在输入 0 时关闭程序。有人有有用的建议吗？我会很感激。^_^

更新：对不起，我忘了提到我还必须包括一个跟踪输入数量的循环计数器，一个确定总值是否小于或大于 100 的注释，以及一个确定总输入数的语句输入。这就是最后的 if else 语句的原因。我尝试取出最后一个 while 语句，因为我知道这是无限循环的原因，但是当我这样做时它不会显示结果。我将代码更改为：

int main ()
{
    int i(1), sum(0);
    int sum2(0);
    const int max(10);

cout << "Enter numbers, one per line. Enter 0 to end:" << endl;

    while (i!=0)
    {
        cin >> i; 
        sum += i; //add current value of i to sum
        sum2 += 1;
    }   
if (sum < 100) // If total is less than 100
            cout << "Thank you. The total was " << sum << endl 
                     << "The total number of inputs reads: " << sum2 << endl
                     << "The total is less than 100." << endl ;
        else // Else total is greater than 100
                cout << "Thank you. The total was " << sum << endl 
                     << "The total number of inputs reads: " << sum2 << endl 
                     << "The total is greater than 100." << endl ;

} //End of Int Main

我的输出应该是

Enter numbers, one per line. Enter 0 to end:
7
8
6
5
5
9
8
0
Thank you. The total was 48.
The total number of inputs read: 8
The total is less than 100.
4

3 回答 3

2

i0退出第一个循环后，它一直停留在并且永远不会改变。不要使用另一个while循环，只需在之后打印结果。

于 2013-01-25T23:19:16.273 回答
1

删除while (i==0). 这将永远是真的。

于 2013-01-25T23:19:17.337 回答
1

你的问题是你第二次while loop循环while (i==0)，但i在循环内永远不会改变。

while (i==0)  // Infinite loop, i is never change inside the block. 
{   
    if (sum < 100)    // If total is less than 100
        cout << "Thank you. The total was " << sum << endl 
                 << "The total number of inputs reads: " << sum2 << endl
                 << "The total is less than 100." << endl ;
    else            // Else total is greater than 100
            cout << "Thank you. The total was " << sum << endl 
                 << "The total number of inputs reads: " << sum2 << endl 
                 << "The total is greater than 100." << endl;
}

这里根本不需要循环构造。

编辑：你想要的是：

#include <iostream>
using namespace std;

int main(int argc, const char* argv[]) {
  int i, sum, count;

  cout << "Enter numbers, one per line. Enter 0 to end:" << endl;

  while (i!=0) {
    cin >> i; 
    sum += i;
    count++;
  }   

  cout << "Thank you. The total was " << sum << endl 
       << "The total number of inputs reads: " << count << endl;

  if (sum < 100)
    cout << "The total is less than 100." << endl;
  else
    cout << "The total is greater than 100." << endl;

  return 0;
}

演示：

$ ./a.out 
Enter numbers, one per line. Enter 0 to end:
1000
100
10
0
Thank you. The total was 1110
The total number of inputs reads: 4
The total is greater than 100.

$ ./a.out 
Enter numbers, one per line. Enter 0 to end:
1
2
3
0
Thank you. The total was 6
The total number of inputs reads: 4
The total is less than 100.

请注意，计数包括终止0，因此您可能想要报告count-1。

于 2013-01-25T23:19:34.330 回答