C++击球率程序文件IO问题：无法输出最高/最低击球率及对应球员

Let's break down and fix the issues in your batting average calculator step by step:

1. Fix the printHigh() and printLow() functions to display player names #

Right now, these functions only print header text—they don't actually iterate through the Stack instances holding the player names for highest/lowest averages. We'll modify them to copy the stack to a temporary one (so we don't empty the original) and print each player:

void Player::printHigh() {
    cout << "Highest batting average is: " << highest << endl;
    cout << "Players with the highest batting average: " << endl;
    
    // Use a temp stack to preserve the original data
    Stack<string> tempHigh = high;
    while (!tempHigh.empty()) {
        cout << "  - " << tempHigh.peek() << endl;
        tempHigh.pop();
    }
}

void Player::printLow() {
    cout << "Lowest batting average is: " << lowest << endl;
    cout << "Players with the lowest batting average: " << endl;
    
    Stack<string> tempLow = low;
    while (!tempLow.empty()) {
        cout << "  - " << tempLow.peek() << endl;
        tempLow.pop();
    }
}

2. Fix the main function's broken file I/O logic #

Your current main has several critical issues:

• It checks if(!infile) after closing the input file, which will always trigger the error message
• It overwrites your original input file (avgs.txt) when opening it for output
• It doesn't actually write any meaningful results to the output file

Here's the corrected version, with clear input/output separation and proper error handling:

#include "Player.h"
#include "Stack.h"
#include <fstream>
#include <iostream>
using namespace std;

int main() {
    Player x;
    string name;
    double avg;
    
    // Step 1: Read input file (check for success first)
    ifstream infile("avgs.txt");
    if (!infile) {
        cout << "Unable to open input file: avgs.txt" << endl;
        return 1;
    }
    
    while (infile >> name >> avg) {
        x.insertPlayer(name, avg);
    }
    infile.close();
    
    // Step 2: Print results to console
    cout << "\n--- Batting Average Results ---" << endl;
    x.printHigh();
    cout << endl;
    x.printLow();
    
    // Step 3: Write results to a separate output file (avoid overwriting input)
    ofstream outfile("results.txt");
    if (!outfile) {
        cout << "Error opening output file: results.txt" << endl;
        return 1;
    }
    
    // Write highest average data to file
    outfile << "Highest batting average is: " << x.highest << endl;
    outfile << "Players with the highest batting average: " << endl;
    Stack<string> tempHigh = x.high;
    while (!tempHigh.empty()) {
        outfile << "  - " << tempHigh.peek() << endl;
        tempHigh.pop();
    }
    
    outfile << endl;
    
    // Write lowest average data to file
    outfile << "Lowest batting average is: " << x.lowest << endl;
    outfile << "Players with the lowest batting average: " << endl;
    Stack<string> tempLow = x.low;
    while (!tempLow.empty()) {
        outfile << "  - " << tempLow.peek() << endl;
        tempLow.pop();
    }
    
    outfile.close();
    cout << "\nResults saved to results.txt!" << endl;
    
    return 0;
}

3. Add safe initialization to the Player class #

To avoid edge cases (like an empty input file), add a constructor to initialize highest and lowest to logical default values for batting averages:

In Player.h:

class Player {
public:
    double lowest;
    double highest;
    Stack<string> low;
    Stack<string> high;
    
    // Initialize lowest to max possible avg (1.0), highest to min (0.0)
    Player() : lowest(1.0), highest(0.0) {}
    
    void insertPlayer(string name, double batAvg);
    void printHigh();
    void printLow();
};

4. Clean up the Stack class #

Your Stack class doesn't need to inherit from exception—this serves no purpose since you're already throwing standard exceptions in pop() and peek(). Fix the class definition in Stack.h:

template <class T>
class Stack {  // Remove ": public exception"
private:
    vector<T> myStacks;
public:
    void push(T const& uStack);
    void pop();
    T peek() const;
    bool empty() const { return myStacks.empty(); }
};

Testing with your sample input #

Using your avgs.txt content:

Orlando .775 Charles .606 J.D. .775 Gina .400 Sam .702 Rich .686

The program will now output to console:

Player Orlando has an average of: 0.775
Player Charles has an average of: 0.606
Player J.D. has an average of: 0.775
Player Gina has an average of: 0.4
Player Sam has an average of: 0.702
Player Rich has an average of: 0.686

--- Batting Average Results ---
Highest batting average is: 0.775
Players with the highest batting average: 
  - J.D.
  - Orlando

Lowest batting average is: 0.4
Players with the lowest batting average: 
  - Gina

Results saved to results.txt!

And results.txt will contain identical results.

内容的提问来源于stack exchange，提问作者Mgonz