方法在不同函数中的变化值。 [英] value of method changing in different functions.

问题描述

i有以下代码;

Hi,

i have the code below;

void exchange(int i, int j, int arr[])
{
	int k=arr[i];
	arr[i] = arr[j];
	arr[j] = k;
}


void partition(int low, int high, int pivotpoint, int arr[],int arraysize)
{
	int i=0, j=0, pivotitem = arr[low];	
	
	j=low;
	for(i=low+1;i<=high;i++)
	{		
		if(arr[i] < pivotitem)
		{					
			j++;
			exchange (i,j,arr);					
		}		
	}
	pivotpoint = j;
	exchange(low,pivotpoint,arr);
}


void quicksort(int low, int high,int arr[],int arraysize, int pivotpoint)
{
	if(high > low)
	{
		partition(low, high, pivotpoint, arr,arraysize);
		quicksort(low,pivotpoint-1,arr,arraysize,pivotpoint);
		quicksort(pivotpoint+1,high,arr,arraysize,pivotpoint);
	}
}

它值为pivotpoint作为j，

但当它转回快速排序功能时，枢轴点的值为钢零，而阵列按编程更改。



为什么它不会更改为新值？

when partition function job ends,
it values pivotpoint as j,
But when it turns back to quicksort function, the value of pivotpoint is steel zero, while the array is changed as programmed.

why doesn''t it change to the new value?

推荐答案

您正在将 pivotpoint 传递给 partition 作为值而不是引用... http://www.learncpp.com/cpp-tutorial/73-passing-arguments-by-reference/ [ ^ ]

You are passing pivotpoint into the partition function as a value instead of a reference ... http://www.learncpp.com/cpp-tutorial/73-passing-arguments-by-reference/[^]

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