BinarySearch.cpp

/**
* Developer: Minhas Kamal (BSSE-0509, IIT, DU)
* Date: 13.Nov.2013
**/

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream list; //input file stream
    list.open("BinarySearch_Input.txt");
    //list.open(argv[1]);

    if(!list.is_open()){   //when file is not found
        cout << "File is not found!\n";
        return 0;
    }

    int member;     //number of integers
    list >> member;

    int myArray[member]; //stores the input data
    for(int i=0; i<member; i++)    //reading the data
        list >> myArray[i];

    ///BinarySearch
    int element;
    cout << "Enter the element: ";
    cin >> element;

    int left=0, //left location of the myArray
        right=member-1, //right location of the myArray
        location=-1;    //the location of the element

    while(right-left > 0){
        int loc = (right+left)/2;

        if(myArray[loc]==element){
            location=loc;
            break;
        }
        else if(myArray[loc]>element){
            right = loc-1;
        }
        else if(myArray[loc]<element){
            left = loc+1;
        }
    }

    if(location==-1) {
        cout << "\nElement is not found! \n";
    }
    else{
        //cout << "\nThe location is: " << location+1 << endl;
        cout << "\n\n";
        for(int i=left; i<=right; i++){
            if(myArray[i]==element) cout << "The location is: " << i+1 << endl;
        }
    }

    list.close();

    return 0;
}

BinarySearch_Input.txt

100
11
12
15
18
19
21
23
26
29
29
33
34
34
34
36
37
38
39
39
40
43
45
45
45
45
45
45
45
46
50
53
54
54
54
56
56
56
56
56
57
57
58
59
60
60
61
64
64
65
65
65
65
65
67
67
67
67
67
68
68
69
69
70
70
70
71
71
73
74
76
76
78
78
78
79
79
81
82
84
85
85
88
89
89
90
90
93
94
94
96
97
97
98
98
99
99
99
100
100
100