Question

我的代码中的所有内容都可以运行，它可以从文件中获取输入，计算平均值和输出。它本身并不是一次性完成的。如果我点击输入它会执行下一行，依此类推，直到文件结束。我如何制作它以便一次性完成所有行？

代码：

/***************************************************/
/* Author:     Sam LaManna                         */
/* Course:     CSC 135 Lisa Frye                   */
/* Assignment: Program 4 Grade Average             */
/* Due Date:   10/10/11                            */
/* Filename:   program4.cpp                        */
/* Purpose:    Write a program that will process   */
/*             students are their grades. It will  */
/*             also read in 10 test scores and     */
/*             compute their average               */
/***************************************************/

#include <iostream>     //Basic input/output
#include <iomanip>      //Manipulators
#include <string>       //String stuff 
#include <fstream>

using namespace std;

void instruct ();       //Function declaration for printing instructionstring studname ();
void input (ifstream &infile, float& test1, float& test2, float& test3, float& test4, float& test5, float& test6, float& test7, float& test8, float& test9, float& test10, string& studentname);      //Function declaration for input
float aver (float test1, float test2, float test3, float test4, float test5, float test6, float test7, float test8, float test9, float test10);      //Function declaration for calculating average
void output (string studentname, float average);      //Function declaration for output



int main()
{
  float test1 = 0;              //Vars (test1 - test10) for test scores
  float test2 = 0;
  float test3 = 0;
  float test4 = 0;
  float test5 = 0;
  float test6 = 0;
  float test7 = 0;
  float test8 = 0;
  float test9 = 0;
  float test10 = 0;
  string studentname = "a";     //Define Var for storing students name
  float average = 0;            //Define var for storing average


  instruct();     //Function call to print instructions


  ifstream infile("grades.dat");

  input (infile, test1, test2, test3, test4, test5, test6, test7, test8, test9, test10, studentname);     //Function call for scores

  while (!infile.eof())
    {
      average = aver (test1, test2, test3, test4, test5, test6, test7, test8, test9, test10);    //Function call for average

      output (studentname, average);     //Function call for output

      cin.ignore(1);

      input (infile, test1, test2, test3, test4, test5, test6, test7, test8, test9, test10, studentname); //Get new input
    }     //end eof

  return 0;
}

/***************************************************/
/* Name: instruct                                  */
/* Description: Print instructions to user.        */
/* Paramerters: N/A                                */
/* Return Value: N/A                               */
/***************************************************/

void instruct()
{
  cout << "\n" << "This program will calculate the average of 10 test scores that are read from a file. " << "\n" << "\n";
  //Prints instructions

  return;
}

/***************************************************/
/* Name: input                                     */
/* Description: Get input                          */
/* Paramerters: N/A                                */
/* Return Value: N/A                               */
/***************************************************/

void input (ifstream& infile, float& test1, float& test2, float& test3, float& test4, float& test5, float& test6, float& test7, float& test8, float& test9, float& test10, string& studentname)

{
  getline(infile, studentname);
  infile >> test1 >> test2 >> test3 >> test4 >> test5 >> test6 >> test7 >> test8 >> test9 >> test10;
  infile.ignore(10, '\n');

  return;
}



/***************************************************/
/* Name: aver                                      */
/* Description: Calculate Average                  */
/* Paramerters: N/A                                */
/* Return Value: aver                              */
/***************************************************/


float aver (float test1, float test2, float test3, float test4, float test5, float test6, float test7, float test8, float test9, float test10)

{
  float aver = 0;
  aver = test1 + test2 + test3 + test4 + test5 + test6 + test7 + test8 + test9 + test10;
  aver = aver / 10;
  return aver;
}


/***************************************************/
/* Name: output                                    */
/* Description: Calculate Average                  */
/* Paramerters: N/A                                */
/* Return Value: aver                              */
/***************************************************/

void output (string studentname, float average)      //Function declaration for output
{ 

  cout << studentname;

  cout << average;

  return;
}

Answer 1

删除

cin.ignore(1);

来自main中的while循环，它阻止程序执行，直到你输入一个char。

哦，在你打开一个关于为什么它在一行上打印的新问题之前，这是因为你输入cin的输入用于推进该行，但现在你应该在输出中添加endl

cout << blah << bleh << endl;

Answer 2

在main功能中，您正在使用

cin.ignore(1);

从cin中提取/等待输入字符并将其丢弃。有关详细信息，请参阅此istream::ignore参考。

删除/注释掉此声明将解决您的问题。

文件不会重复，直到文件结束

2 个答案: