C ++ Newbie需要帮助打印整数的组合 [英] C++ Newbie needs helps for printing combinations of integers

问题描述

假设我得到：

1. 整数范围 iRange 从 1 最多到 iRange ）和


2. / li>
   

我想查找所有可能组合的数目并打印出所有这些组合。

例如：

给定： iRange = 5 和 n = 3

然后组合的数量是 iRange！ /（（iRange！-n！）* n！）= 5！ /（5-3）！ * 3！ = 10 组合，输出为：

  123  -  124  -  125  -  134  - 145  -  234  -  235  -  245  -  345 
  

另一个例子：

给定： iRange = 4 和 n = 2 p>

那么组合的数量是 iRange！ /（（iRange！-n！）* n！）= 4！ /（4-2）！ * 2！ = 6 组合，输出为：

  12  -  13  -  14  -  23  -  24  - 34 
  

我到目前为止的尝试是：

  #include< iostream> 
 using namespace std; 
 
 int iRange = 0; 
 int iN = 0; 
 
 int fact（int n）
 {
 if（n <1）
 return 1; 
 else 
 return fact（n-1）* n; 
} 
 
 void print_combinations（int n，int iMxM）
 {
 int iBigSetFact = fact（iMxM）; 
 int iDiffFact = fact（iMxM-n）; 
 int iSmallSetFact = fact（n）; 
 int iNoTotComb =（iBigSetFact /（iDiffFact * iSmallSetFact））; 
 cout<<可能的组合的数量是： cout<<，这些组合如下：<< endl; 
 
 
 int i，j，k; 
 for（i = 0; i  {
 for（j = i + 1; j  {
 // for（k = j + 1; k  cout<< i + 1<< j + 1& 
} 
} 
} 
 
 int main（）
 {
 cout<<请提供范围将找到组合：<<< endl; 
 cin>> iRange; 
 cout<<请给出所需的组合数：<< endl; 
 cin>> iN; 
 print_combinations（iN，iRange）; 
 return 0; 
} 
  

我的问题：
的我的代码相关的打印的组合只适用于 n = 2，iRange = 4 ，我不能让它一般工作，即任何 n 和 iRange 。

解决方案

以下是您的代码已修改：D：D使用递归解决方案：

  #include < iostream> 
 
 int iRange = 0; 
 int iN = 0; //从iRange获取的项目数，对于这些项目，我想打印出组合
 int iTotalCombs = 0; 
 int * pTheRange; 
 int * pTempRange; 
 
 int find_factorial（int n）
 {
 if（n <1）
 return 1; 
 else 
 return find_factorial（n-1）* n; 
} 
 
 // --->这里是另一个解决方案：
 void print_out_combinations（int * P，int K，int n_i）
 {
 if（K == 0）
 {
 for（int j = iN; j> 0; j--）
 std :: cout<< P [j] ;; 
 std :: cout<< std :: endl; 
} 
 else 
 for（int i = n_i; i  {
 P [K] = pTheRange [i] 
 print_out_combinations（P，K-1，i + 1）; 
} 
} 
 //这里结束了解决方案... 
 
 int main（）
 {
 std :: cout< ;给出项目集-iRange- =; 
 std :: cin>> iRange; 
 std :: cout<<给出要创建组合的iRange的项目＃-iN- =; 
 std :: cin>> iN; 
 
 pTheRange = new int [iRange]; 
 for（int i = 0; i< iRange; i ++）
 {
 pTheRange [i] = i + 1; 
} 
 pTempRange = new int [iN]; 
 
 iTotalCombs =（find_factorial（iRange）/（find_factorial（iRange-iN）* find_factorial（iN）））; 
 
 std :: cout<<可能的组合数是：<  std :: cout<<因为从一组大小< iRange<<中绘制的 print_out_combinations（pTempRange，iN，0）; 
 return 0; 
} 
  

Suppose I am given:

1. A range of integers iRange (i.e. from 1 up to iRange) and
2. A desired number of combinations

I want to find the number of all possible combinations and print out all these combinations.

For example:

Given: iRange = 5 and n = 3

Then the number of combinations is iRange! / ((iRange!-n!)*n!) = 5! / (5-3)! * 3! = 10 combinations, and the output is:

123 - 124 - 125 - 134 - 135 - 145 - 234 - 235 - 245 - 345

Another example:

Given: iRange = 4 and n = 2

Then the number of combinations is iRange! / ((iRange!-n!)*n!) = 4! / (4-2)! * 2! = 6 combinations, and the output is:

12 - 13 - 14 - 23 - 24 - 34

My attempt so far is:

#include <iostream>
using namespace std;

int iRange= 0;
int iN=0;

int fact(int n)
{
    if ( n<1)
    	return 1;
    else
    return fact(n-1)*n;
}

void print_combinations(int n, int iMxM)
{
    int iBigSetFact=fact(iMxM);
    int iDiffFact=fact(iMxM-n);
    int iSmallSetFact=fact(n);
    int iNoTotComb = (iBigSetFact/(iDiffFact*iSmallSetFact));
    cout<<"The number of possible combinations is: "<<iNoTotComb<<endl;
    cout<<" and these combinations are the following: "<<endl;


    int i, j, k;
    for (i = 0; i < iMxM - 1; i++)
    {
    	for (j = i + 1; j < iMxM ; j++)
    	{
    		//for (k = j + 1; k < iMxM; k++)
    			cout<<i+1<<j+1<<endl;
    	}
    }
}

int main()
{
    cout<<"Please give the range (max) within which the combinations are to be found: "<<endl;
    cin>>iRange;
    cout<<"Please give the desired number of combinations: "<<endl; 
    cin>>iN;
    print_combinations(iN,iRange);
    return 0;	
}

My problem: The part of my code related to the printing of the combinations works only for n = 2, iRange = 4 and I can't make it work in general, i.e., for any n and iRange.

解决方案

Here is your code edited :D :D with a recursive solution:

#include <iostream>

int iRange=0;   
int iN=0;   		//Number of items taken from iRange, for which u want to print out the combinations
int iTotalCombs=0;
int* pTheRange;
int* pTempRange;

int find_factorial(int n)
{
    if ( n<1)
        return 1;
    else
    return find_factorial(n-1)*n;
}

//--->Here is another solution:
void print_out_combinations(int *P, int K, int n_i) 
{
    if (K == 0)
    {
    	for (int j =iN;j>0;j--)
    	std::cout<<P[j]<<" ";
    	std::cout<<std::endl;
    }
    else
        for (int i = n_i; i < iRange; i++) 
    	{
            P[K] = pTheRange[i];
            print_out_combinations(P, K-1, i+1);
        }
}
//Here ends the solution...

int main() 
{
    std::cout<<"Give the set of items -iRange- = ";
    std::cin>>iRange;
    std::cout<<"Give the items # -iN- of iRange for which the combinations will be created = ";
    std::cin>>iN;

    pTheRange = new int[iRange];
    for (int i = 0;i<iRange;i++)
    {
    	pTheRange[i]=i+1;
    }
    pTempRange = new int[iN];

    iTotalCombs = (find_factorial(iRange)/(find_factorial(iRange-iN)*find_factorial(iN)));

    std::cout<<"The number of possible combinations is: "<<iTotalCombs<<std::endl;
    std::cout<<"i.e.the combinations of "<<iN<<" elements drawn from a set of size "<<iRange<<" are: "<<std::endl;
    print_out_combinations(pTempRange, iN, 0);
    return 0;
}

这篇关于C ++ Newbie需要帮助打印整数的组合的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！