**Divide and conquer** is a *problem-solving technique* that is commonly used in computer science and programming. The basic idea behind this technique is to* break down a large problem into smaller, more manageable sub-problems*, solve each sub-problem independently, and then combine the solutions to the sub-problems to obtain the solution to the original problem. Here’s how you can use the **divide and conquer** approach in C language:

**Divide**: Break down the original problem into smaller sub-problems that can be solved independently. This can be done recursively until the sub-problems are simple enough to be solved directly.**Conquer**: Solve each sub-problem independently using a suitable algorithm. This can be done using any appropriate algorithmic approach, such as dynamic programming, greedy algorithms, or backtracking.**Combine**: Combine the solutions to the sub-problems to obtain the solution to the original problem. This can involve merging sorted lists, summing values, or other operations that are specific to the problem being solved.

Let’s take an example of finding the maximum element in an array using divide and conquer approach:

**Divide**: Divide the array into two halves.**Conquer**: Find the maximum element in each half of the array using recursion.**Combine**: Compare the maximum elements of the two halves and return the maximum of the two.

Here is the C code that implements this approach:

```
int findMax(int arr[], int start, int end) {
if (start == end) {
return arr[start];
}
int mid = (start + end) / 2;
int max1 = findMax(arr, start, mid);
int max2 = findMax(arr, mid + 1, end);
return (max1 > max2) ? max1 : max2;
}
```

This function takes an array, a starting index, and an ending index as input and returns the maximum element in the array. The function recursively divides the array into halves, finds the maximum element in each half using recursion, and then compares the maximum elements to return the maximum of the two.

The **divide and conquer** approach can be used to solve a wide variety of problems in computer science, such as *sorting, searching, and graph algorithms*.