#include<stdio.h>

main()
{
int a[50],i,n,key;
printf("Enter the size of the array:\n");
scanf("%d",&n);
printf("Enter elements into the array in ascending order:");
for(i=0; i<n; i++) {
scanf("%d",&a[i]);
}

printf("The sorted array is: ");
for(i=0; i<n; i++) {
printf("%d\t",a[i]);
}

printf("\nEnter the element to be searched: ");
scanf("%d",&key);


int start=0;
int end=n-1;

while(start<=end)
{
int m=(a[end]-a[start])/(end-start);
int Pos=start+(key-a[start])/m;

if(a[Pos]==key)
{
printf("%d found at %d",key,Pos+1);
break;
}
else if(a[Pos]>key)
{
end=Pos-1;

}
else
{
start=Pos+1;

}
printf("Element Not Found!!");
break;
}

}
     
           
Note: Need to be arranged in compiler after copied
   

 OutPut:

Enter the size of the array: 4 Enter elements into the array in ascending order:1 2 5 7 The sorted array is: 1 2 5 7 Enter the element to be searched: 5 5 found at 3