We suggest you do not use library functions for binary search as its very likely that you will be explicitly asked to implement the binary search in interviews.

##### Implementation of Binary Search

```
// binary search example in C/C++
/* here Arr is an of integer type, n is size of array
and target is element to be found */
int binarySearch(int *Arr, int n, int target) {
//set stating and ending index
int start = 0, ending = n-1;
while(start <= ending) {
// take mid of the list
int mid = (start + end) / 2;
// we found a match
if(Arr[mid] == target) {
return mid;
}
// go on right side
else if(Arr[mid] < target) {
start = mid + 1;
}
// go on left side
else {
end = mid - 1;
}
}
// element is not present in list
return -1;
}
```

```
// binary search example in Java
/* here Arr is an of integer type, n is size of array
and target is element to be found */
int binarySearch(int Arr[], int n, int target) {
//set stating and ending index
int start = 0, ending = n-1;
while(start <= ending) {
// take mid of the list
int mid = (start + end) / 2;
// we found a match
if(Arr[mid] == target) {
return mid;
}
// go on right side
else if(Arr[mid] < target) {
start = mid + 1;
}
// go on left side
else {
end = mid - 1;
}
}
// element is not present in list
return -1;
}
```

```
# binary search example in Python
# here Arr is an of integer type, n is size of array
# and target is element to be found
def binarySearch(Arr, n, target) :
#set stating and ending index
start, end = 0, n-1
while start <= end :
mid = (start + end) / 2
# we found a match
if Arr[mid] == target :
return mid
# go on right side
elif Arr[mid] < target :
start = mid + 1
# go on left side
else :
end = mid - 1;
# element is not present in list
return -1
```

**Walkthrough Examples :**