# What Is Graph in Data Structure in C?

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Heather Bennett

What Is Graph in Data Structure in C?

A graph is a non-linear data structure that consists of a set of nodes (also known as vertices) connected by edges. It is used to represent relationships between different objects or entities. In C, graphs can be implemented using various data structures and algorithms.

## Types of Graphs

There are several types of graphs, including:

• Undirected Graph: In an undirected graph, the edges do not have any direction. The relationship between the nodes is symmetric.
• Directed Graph: In a directed graph (also known as a digraph), the edges have a direction. The relationship between the nodes is asymmetric.
• Weighted Graph: In a weighted graph, each edge has an associated weight or cost that represents some value or distance.
• Cyclic Graph: A cyclic graph contains one or more cycles, which are paths that start and end at the same node.
• Acyclic Graph: An acyclic graph does not contain any cycles.

## Graph Representation

In C, graphs can be represented using various data structures such as adjacency matrices and adjacency lists.

An adjacency matrix is a two-dimensional array where each cell represents whether there is an edge between two nodes. If there is an edge between node i and node j, then matrix[i][j] will be set to 1; otherwise, it will be set to 0. This representation is suitable for dense graphs where most of the cells have non-zero values.

```Example:
0 1 0 0
1 0 1 1
0 1 0 1
0 1 1 0
```

An adjacency list is a collection of linked lists or arrays where each node has a list of its neighboring nodes. This representation is suitable for sparse graphs where only a few nodes are connected to each other.

```Example:
Node 0: [1]
Node 1: [0,2,3]
Node 2: [1,3]
Node 3: [1,2]
```

## Graph Traversal

Graph traversal refers to visiting all the nodes of a graph in a specific order. Two common methods for graph traversal are depth-first search (DFS) and breadth-first search (BFS).

Depth-First Search (DFS): In DFS, we start from an initial node and explore as far as possible along each branch before backtracking. It uses a stack data structure to keep track of the visited nodes.

Breadth-First Search (BFS): In BFS, we start from an initial node and explore all its neighboring nodes before moving on to their neighbors. It uses a queue data structure to keep track of the visited nodes.

## Applications of Graphs

Graphs have numerous applications in various fields, including:

• Social networks analysis
• Route planning and optimization
• Network flow analysis
• Data mining and machine learning algorithms
• Scheduling and task allocation
• And many more!

Understanding graphs and their implementation in C is essential for solving complex problems that involve relationships between entities or objects. By leveraging the power of graphs, you can efficiently model and analyze real-world scenarios.

Now that you have a better understanding of graphs in data structure in C, you can start exploring various graph algorithms and applications to expand your knowledge further.