折半查詢(C++實現)

學億點點發表於2020-12-07
#include<iostream>
#include<stdlib.h>
using namespace std;
#define MaxNumber 100
int *Number = new int[MaxNumber];

void found(int a, int data[],int b, int length) {
	if (b + 1 == length) {
		if (data[b] == a) {
			cout << "--------------------------" << endl;
			cout << "已找到,在第" << b+1 << "位" << endl;
			cout << "--------------------------" << endl;
		}
		else {
			if (data[length] == a) {
				cout << "--------------------------" << endl;
				cout << "已找到,在第" << (length + b) / 2 + 1 << "位" << endl;
				cout << "--------------------------" << endl;
			}
			else {
				cout << "--------------------------" << endl;
				cout << "陣列裡沒有這個數字" << endl;
				cout << "--------------------------" << endl;
			}
		}
	}
	else {
		if (data[(length+b) / 2] > a) {
			found(a, data, 0, (length + b) / 2);
		}
		if (data[(length+b) / 2] < a) {
			found(a, data, (length + b) / 2, length);
		}
		if (data[(length + b) / 2] == a) {
			cout << "--------------------------" << endl;
			cout << "已找到,在第" << (length + b) / 2+1 << "位" << endl;
			cout << "--------------------------" << endl;
		}
	}
	
}
int main() {
	int length = 0;
	cout << "輸入陣列長度:";
	cin >> length;
	cout << endl;
	cout << "輸入陣列:";
	for (int i = 0; i < length; i++)
	{
		cin >> Number[i];
	}
	cout << endl;
	cout << "-----------------------------" << endl;
	cout << "	資料錄入完畢      " << endl;
	cout << "-----------------------------" << endl;
	int num = 0;
	for (int i = 0; i < length; i++)
	{
		for (int j = i+1; j < length; j++)
		{
			if (Number[i] > Number[j]) {
				num = Number[i];
				Number[i] = Number[j];
				Number[j] = num;
			}
		}
	}
	cout << "陣列為:";
	for (int i = 0; i < length; i++)
	{
		cout<<Number[i]<<"  ";
	}
	cout << endl;
	bool a = true;
	while (a) {
		int number = 0;
		cout << "輸入需要搜尋的數字:";
		cin >> number;
		found(number,Number,0,length-1);
		cout << "是否繼續?(是輸入1,否輸入其他數)" << endl;
		int b = 0;
		cin >> b;
		if (b == 1) {
			a = true;
		}
		else {
			a = false;
		}
	}
	
}

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