c++ - 从返回 int c++ 的函数中获取二维数组

Question

我有一项模拟骰子游戏的作业。作为程序的一部分，用户输入要掷骰子的数量和掷骰子的次数。如果用户掷 4 个骰子，程序应将 4 个值相加，将结果存储在数组中，然后按照用户定义的次数重做程序。主要代码和函数原型(prototype)由导师定义，不可修改。我们必须编写函数。

在main的第3步中，有两个for循环。内部 for 循环调用相关函数。二维数组 rollSums[][] 被分配给函数的结果。该数组将在另一个函数中使用。我不知道如何从函数中正确填充二维数组。代码和我对该功能的尝试如下:

#include <iostream>
#include <iomanip>
#include <cstdlib> // needed for functions srand() and rand()
#include <ctime> // needed for function time()
#include <cmath> // needed for sqrt()

using namespace std;

const int MAXNUMTOROLL=10;
const int MAXROLLS=100;


int rollDice(int diceVals[], int numToRoll);

int main()
{
  int sum;
  int rollSums[MAXNUMTOROLL][MAXROLLS];
  int diceVals[MAXROLLS];
  double mean[MAXNUMTOROLL], std[MAXNUMTOROLL];
  int numToRoll, numRolls;

  srand(time(NULL));

  // STEP 1: Ask user to input the maximum number of dice to use:

  cout << "Please enter the maximum number of dice to use:" << endl;
  do 
    {
      cin >> numToRoll;
    } while (numToRoll < 0 || numToRoll > MAXNUMTOROLL); 

  cout << "Please enter the number of rolls:" << endl;

  // STEP 2: Ask user to input the number of rolls to carry out:
  do
    {
      cin >> numRolls;
    } while (numRolls < 0 || numRolls > MAXROLLS);

  // STEP 3: For k=1 to numToRoll, simulated numRolls rolls of the dice
  // and store the sum of the numbers rolled in the array rollSums[][]

  for (int k=1;k<=numToRoll;k++)
    {
      for (int i=0;i<numRolls;i++)
    {
      rollSums[k-1][i] = rollDice(diceVals, k);
    }
    }

  return 0;
}

int rollDice(int diceVals[], int numToRoll) //function simulating throwing of dice
{
 int sum=0;
 int i=0;

 for(i=0;i<numToRoll;i++)
 {
  diceVals[i]=1+rand()%6;
  sum=sum+diceVals[i];
 }
 return sum;
}

Answer 1

adohertyd，请参阅我在代码示例中的注释:

#include <iostream>
#include <iomanip>
#include <cstdlib> // needed for functions srand() and rand()
#include <ctime> // needed for function time()
#include <cmath> // needed for sqrt()

using namespace std;

const int MAXNUMTOROLL=10;
const int MAXROLLS=100;
const bool show_debug = true;

int rollDice(int diceVals[], int numToRoll);

int main()
{
    int roll_Sums[MAXNUMTOROLL];
    int diceVals[MAXROLLS];
    //double mean[MAXNUMTOROLL], std[MAXNUMTOROLL];
    int numDice, numThrows;

    //Initialize random number generator with the current time
    srand(time(NULL));

    // STEP 1: Ask user to input the maximum number of dice to use:
    cout << "Please enter the maximum number of dice to use:" << endl;

    // STEP 2: Validate number of dice input
    do 
    {
        cin >> numDice;
    } while (numDice < 0 || numDice > MAXNUMTOROLL); 

    //STEP 3: Ask user to input the number of times to throw each dice
    cout << "Please enter the number of rolls:" << endl;

    // STEP 4: Validate number of throws input
    do
    {
        cin >> numThrows;
    } while (numThrows < 0 || numThrows > MAXROLLS);

    cout << "\n\nThrowing Dice Now...\n\n";

    // STEP 5: Roll the dice
    //The loop deals with each dice
    for (int diceCount = 0; diceCount < numDice; diceCount++)
    {
        //The function call deals with all the throws per dice
        //Note: roll_Sums array didn't need to be two dimensional, 
        //      also, rollDice gets passed diceVals[] by value and the number of throws to execute
        roll_Sums[diceCount] = rollDice(diceVals, numThrows);

        //Debug output
        if(show_debug)
        {
            //Since roll_Sums is zero based, add one to the visible index so the user doesn't get confused :P
            cout << "Roll Sum for dice #" << diceCount + 1 << ": " << roll_Sums[diceCount] << endl << endl;
        }      
    }

    return 0;
}

//rollDice() returns the sum of all the dice rolls it performed 
int rollDice(int diceVals[], int numToRoll)
{
    int sum=0;

    for(int i=0;i<numToRoll;i++)
    {
        //Get your random dice rolls
        diceVals[i]=1+rand()%6;

        //Debug output
        if(show_debug)
        {
            cout << "Dice Roll # " << i+1 << ": " << diceVals[i] << endl; 
        }

        //Accumulate your value, e.g. "sum"
        sum += diceVals[i];
    }

    return sum;
}