Doubling search

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <iso646.h>
#include <malloc.h>

int main(){
    int n = 0, targed = 0, first = 0, last = 0,  middle = 0, index = 1;
    printf("Input count: \n");
    scanf("%d", &n);

    int* arr = (int*)malloc(n * sizeof(int));
    for (int i = 0; i < n; i++)
        scanf("%d", &arr[i]);
    printf("Mas: \n");
    for (int i = 0; i < n; i++)
        printf("%d ", arr[i]);
    printf("\nInput target: \n");
    scanf("%d", &targed);

    while (arr[index] < targed)
        index *= 2;


    first = index / 2;
    last = index;
    middle = (first + last) / 2;
    while (first <= last){
        if (arr[middle] == targed){
            printf("El has index: %d", middle + 1);
            break;
        }
        else if (arr[middle] > targed)
            last = middle - 1;
        else if (arr[middle] < targed)
            first = middle + 1;
        middle = (first + last) / 2;
    }

    if (first > last)
        printf("Not found el");

    return 0;
}