Binary_Search.rs

// Rust program for Binary Search
use std::io;

fn main() {
    println!(" Enter number of elements to be entered in the array ");
    let mut size = String::new();
    
    io::stdin().read_line(&mut size).expect("failed to read input.");
    let size: usize = size.trim_end().parse().expect("invalid input");
    let mut vector: Vec<usize> = Vec::with_capacity(size as usize);
    
    println!("Enter element to be searched " );
    let mut element = usize::new();

    println!("Enter elements of array in a sorted array ");
    let mut index = 0;
    
    // Enter values into vector
    while index < size {
        index += 1;
        // Note: Rust takes spaces as non-intergral value
        let mut temp_arr = String::new();
        io::stdin().read_line(&mut temp_arr).expect("failed to read input.");
        let temp_arr: usize = temp_arr.trim_end().parse().expect("invalid input");
        vector.push(temp_arr);
    }
    
    // Binary Search process
    let mut leftpart = 0;
    let mut rightpart = size - 1;
    let mut midindex = 0;
    let mut checkpoint = 0;
    while leftpart <= rightpart {
        midindex = leftpart + (rightpart - leftpart) / 2;

        // Element found
        if vector[midindex] == element{
            checkpoint = 1;
            println!("Element is found at index ");
            println!("{:?}" , midindex + 1);
            break;
        }

        else if vector[midindex] < element{
            leftpart = midindex + 1;
        }

        else {
            rightpart = midindex - 1;
        }
         
    }
    
    if checkpoint == 0 {
        println!("Element is not found in the array ");
    }
}
/* 
TEST CASE

INPUT
 Enter number of elements to be entered in the array                                                                          
3                     
Enter element to be searched 
2                                                                                                        
Enter elements of array in a sorted array                                                                                                       
1                                                                                                                             
2                                                                                                                             
3  

OUTPUT
Element is found at index 
2

INPUT
 Enter number of elements to be entered in the array                                                                          
3                     
Enter element to be searched 
5                                                                                                       
Enter elements of array in a sorted array                                                                                                    
1                                                                                                                             
2                                                                                                                             
3  

OUTPUT
Element is not found in the array 
*/