北京理工大學上機題——二分查找
題目描述:
二分查找{-36,-25,0,12,14,29,35,47,76,100},對上述十個數進行二分查找
測試用例:
請輸入要查找的數據:14 14是第5個數,查找次數爲1
請輸入要查找的數據:-25 -25是第2個數,查找次數爲2
請輸入要查找的數據:121 查找失敗
二分查找也叫折半查找,有關折半查找介紹:折半查找
#include<iostream>
using namespace std;
void search(int num[], int n, int searchNum) {
int count = 0;
int first = 0, end = n - 1;
bool find = false;
int mid;
while (first <= end && !find) {
count++;
mid = (first + end) / 2;
if (searchNum == num[mid]) {
find = true;
break;
}
else if (searchNum < num[mid]) {
end = mid - 1;
}
else {
first = mid + 1;
}
}
if (find) {
cout << searchNum << "是第" << mid + 1 << "個數,查找次數爲" << count << endl;
}
else
cout << "查找失敗" << endl;
}
int main() {
int num[10] = { -36,-25,0,12,14,29,35,47,76,100 };
int searchNum;
int count = 3;
while (count) {
cout << "輸入要查找的數據:";
cin >> searchNum;
search(num, 10, searchNum);
count--;
}
return 0;
}
運行測試結果: