Question

Write a program of Binary Search in C++ by using function and arrays with the explanation.

Answer 1

#include<iostream>
using namespace std;
int main()
{
int BSearch(int [],int,int); //declaring a BSearch()_to search position of given element
int N,i,A[50],E,X;
cout<<"Enter number of elements:"; //input size of array
cin>>N;
cout<<"\nEnter elements\n"; //input elements of array
for(i=0;i<N;++i)
{
cin>>A[i];
}
cout<<"\nElement to search:"; //input element to earch
cin>>E;
  
X=BSearch(A,N,E); // initialize the value of function to variable X
if(X!=-1) //IF VALUE OF x IS NOT -1 THEN PRINT THIS STATEMENT
cout<<"\n Position of element is "<<X+1;
else
cout<<"\nNo element found!";

return 0;
}

int BSearch(int A[],int N,int E) // Function to search element ina array
{
int Fst,Lst,Mid; // Taking variable Fst(First position ),Lst(Last position) and Mid(Middle of array)
Fst=0; Lst=N-1;
  
while(Fst<=Lst) // execute the loop when value of First is lessthen last
{
Mid=(Fst+Lst)/2; // Finding the middle of array
if(E==A[Mid]) //if element is equal to value of element at position Mid
return(Mid); // return the value to X
else
if(E>A[Mid]) // if element is greater element at positon mid
Fst=Mid+1; // then the value of First will be Middle +1 and last will be same and search again between this position
else
Lst=Mid-1;
}
return -1;
}