I received this error for a binary search programme in C, despite the fact that it requested for inputs and produced the right output. The error message I received in the output window is shown below.

```
binarysearch.c: In function 'sort': binarysearch.c:22:5: warning:
implicit declaration of function 'bin'
[-Wimplicit-function-declaration]
bin(a,size);//invokes bin(int,int) to find element
^~~ binarysearch.c: At top level: binarysearch.c:24:6: warning: conflicting types for 'bin' void bin(int a[],int size)//finds element
using binary sort technique and return its index
^~~ binarysearch.c:22:5: note: previous implicit declaration of 'bin' was here
bin(a,size);//invokes bin(int,int) to find element
^~~
Enter size of array
```

How can I fix the problem?

What does the error indicate?

Why did it continue to ask for inputs after an error occurred?

I created two functions. As mentioned in this documentation, the first function, void sort(int a[],int size), used selection sort to sort the array and printed it before invoking the second function, void bin(int a[],int size), which used binary search to find an element and printed its position(index+1). The main function was then written.

The programme is as follows:

```
#include<stdio.h>
void sort(int a[],int size)//sorts array in ascending order
{
int min;
for(int i=0;i<size;i++)
{
for(int j=0;j<size;j++)
{
if(a[j]>a[j+1])//checks if elements at position 'i' is greater than element at position (i+1) and exchanges values if true
{
min=a[j];
a[j]=a[j+1];
a[j+1]=min;
}
}
}
printf("Sorted array:");
for(int i=0;i<size;i++)//prints sorted array
{
printf("%d ",a[i]);
}
bin(a,size);//invokes bin(int,int) to find element
}
void bin(int a[],int size)//finds element using binary sort technique and return its index
{
int key;//stores element to be found
printf("\nEnter element to be found:");
scanf("%d",&key);
int sp=0;//stores starting point which is initially 0
int ep=size-1;//stores ending point which is initially one less than size of array
int mid;//stores average of sp and ep
int count=0;//counter
printf("Occurrence is:");
while(sp<=ep)
{
mid=(sp+ep)/2;
if(a[mid]>key)//to run loop for elements that are before mid
{
ep=mid-1;
}
else if(a[mid]<key)//to run loop for elements that are after mid
{
sp=mid+1;
}
else if(a[mid]==key)//when element is found
{
printf("%d",mid+1);
count+=1;
break;//to stop the loop
}
}
if(count==0)//in case element is not found
printf("ELEMENT NOT FOUND");
}
int main()
{
int n;//stores size of array
printf("Enter size of array:");
scanf("%d",&n);
int arr[n];//creates array of size n
printf("Enter elements:");
for(int i=0;i<n;i++)
{
scanf("%d",&arr[i]);
}
sort(arr,n);//invoke sort(int,int) function which later invokes bin(int,int) function
return 0;
}
```