C ++程序永远循环

Question

I seem to be having an issue that I've been stuck on for hours. I run the program, and it just hangs after asking for the user input. My computer also begins to slow down unless I terminate the program. I have no idea what the problem is. I have tried commenting out code to see where the issue may be coming from. I put a cout statement after asking for the input, and even that does not display.

#include <iostream>
#include <vector>
#include <stdexcept>
#include <iomanip>
#include <cstdlib>
#include <array>
#include "problem2.h"

using namespace std;

int binarySearch(int array[], int input);
void selectSort(int arr[], int n);

int problem2() {
    srand(time(0));         // generate seed based on current system time

    int rand[20];
    int result;
    int input = 1;


    cout << "Enter a number to search for: ";
    cin >> input;

    cout << "testset ";

    for (int z = 0; z < 19; z++) {
        rand[z] = random() % 70;
        cout << rand[15];
    }


    selectSort(rand, 20);


    for (int t = 0; t < 20; t++) {
        //cout << random1D[z];
        }
    result = binarySearch(rand, input);
    //cout << result;

    return 0;
    }

int binarySearch(int arr[], int a) {
    int high = 19;
    int middle =  19/2;
    int low = 0;

    while (arr[middle] != a && low<= high) {
        if (arr[middle] > a) {
            high = middle - 1;
        } else {
            low = middle - 1;
        }

        if (low > high) {

        }
    }
    return middle;
}

void selectSort(int arr[], int n) {
    int min, temp;

    for (int i = 0; i < n-1; i++) {
        min = i;

        for (int j = i + 1; j < n; j++) {
            if (arr[j] < arr[min])
                   min = j;
        }
        if (min != i) {
            temp = arr[i];
            arr[i] = arr[min];
            arr[min] = temp;
        }
    }
}

Answer 1

You have several loops, but all of them except for one have explicit termination. The for loops all end after a specific number of iterations, but your while loop is less certain. Your low is likely never going to be greater than your high , so the loop just keeps going.

Consider changing to low = middle + 1 or altering your logic to more likely ensure that low will eventually overtake high . Or, change the condition the while loop checks.