C++ Programming Code Examples
C++ > Sorting Searching Code Examples
C++ Program to Compare Binary and Sequential Search
/* C++ Program to Compare Binary and Sequential Search
- Implement both binary and sequential search.
- The time complexity of Binary search is O(log(n)).
- The time complexity of Linear search is O(n).
- Implement the binary search and count the number of iteration to compute the result.
- Implement the linear search and count the number of iteration to compute the result.
- Compare the number of iteration and show the better algorithm.
- Exit. */
#include<iostream>
using namespace std;
// A function implementing Binary search on a sorted array.
int BinarySearch(int a[], int start, int end, int item, int iter)
{
int i, mid;
// Every time this function called, counted as a iteration of binary search.
cout<<"\niteration "<<iter+1;
iter++;
// Assigning middle of the array.
mid = start + (end-start+1)/2;
// If value is less than value at start index more than end index then item is not in the array.
if(item > a[end] || item < a[start] || mid == end)
{
cout<<"\nNot found";
return iter;
}
// Return if item found at mid index.
else if(item == a[mid])
{
cout<<"\n item found at "<<mid<<" index.";
return iter;
}
// Return if item found at start index.
else if(item == a[start])
{
cout<<"\n item found at "<<start<<" index.";
return iter;
}
// Return if item found at end index.
else if(item == a[end])
{
cout<<"\n item found at "<<end<<" index.";
return iter;
}
// According to the item value choose the partion to proceed further.
else if(item > a[mid])
BinarySearch(a, mid, 19, item, iter);
else
BinarySearch(a, start, mid, item, iter);
}
// A function implementing Binary search on a sorted array.
int LinearSearch(int a[], int n, int item)
{
int i;
for(i = 0; i < n; i++)
{
cout<<"\niteration "<<i+1;
// Directly comparing the item with the array element sequentially.
if(a[i] == item)
{
cout<<"\n item found at "<<i<<" index.";
// Returning the number of iteration taken place.
return i+1;
}
}
cout<<"\nNot found";
}
int main()
{
int n, i, Biter, Liter, a[20]={1, 9, 16, 24, 28, 35, 39, 43, 49, 53, 55, 66, 67, 73, 75, 77, 83, 89, 96, 97};
cout<<"\nEnter the element to be searched: ";
cin>>n;
cout<<"\n\n\t\t\tBinary Search :";
cout<<"\n\t\t\t*************";
Biter = BinarySearch(a, 0, 19, n, 0);
cout<<"\n\n\t\t\tLinear Search :";
cout<<"\n\t\t\t*************";
Liter = LinearSearch(a, 20, n);
// Comparing the number of iteration and printing the better approach for this search.
if(Liter > Biter)
cout<<"\n\nBinary search is better for this search.";
else if(Liter < Biter)
cout<<"\n\nLinear search is better for this search.";
else
cout<<"\n\nBoth are equally efficient for this search.";
return 0;
}
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