#include<stdio.h>

//列印標準輸出行，加上行號
void Print() 
{
	int line = 1;
	int ch;
	int flg = 1;//1代表在行的開始   0代表不在行的開始
	while((ch = getchar()) != EOF)//EOF:測試檔案尾
	{
		if(flg == 1)
		{
			if(ch == 'q' || ch == 'Q') {return;}//遇q結尾
			printf("%d: ",line);//列印行
			line++;
			flg = 0;
		}
		if(ch == '\n')
		{
			flg = 1;
		}
		putchar(ch);//輸出行值
	}
}
//從標準輸入中讀入字元，並計算checksum的值
int CheckSum() 
{
	int ch;
	signed char sum = -1;
	while((ch = getchar()) != '\n')
	{
		sum += ch;
		printf("%c",ch);
	}
	sum += '\n';
	//Hello world!102
	return sum;
}

//一個有序陣列，兩個值相加，和為key   把這兩個下標儲存下來
void SumK(int *arr,int key,int *num1,int *num2,int len)
{
	int low = 0;
	int high = len-1;
	int sum = 0;
	while(low < high)
	{
		sum = arr[low] +arr[high] ;
		if(sum == key)
		{
			*num1 = low;
			*num2 = high;
			break;
		}
		else if(sum < key)//15  < 20
		{
			low++;
		}
		else
		{
			high--;
		}
	}
}

int main()
{
	int arr[] = {4,6,8,9,10,11,13,23};
	int len = sizeof(arr)/sizeof(arr[0]);
	int index1 = -1;
	int index2 = -1;
	SumK(arr,21,&index1,&index2,len);
	printf("%d,%d\n",index1,index2);
	/*Print();
	printf("%d\n",CheckSum());*/
	getchar();
	return 0;
}