Do you know what is “Dijkstra’s Algorithm in C++” programming language is? Do you find it hard to understand Dijkstra’s algorithm and how to implement it?
Let us try to understand the Algortihm’s for easy implementation of the code.
In this article, we will gain in-depth knowledge about what is Dijkstra’s algorithm in C++ and how can we implement it to solve real-world problems. So, without waiting any further, let us dive in!
Summary Of The Article:
- Dijkstra’s Algorithm is also known as the shortest path-finding algorithm.
- This is used in cases where we need to find out the shortest distance or path from one vertex to all the others in a graph.
- In real life, Dijkstra’s algorithm is used in real-time navigation systems to find the suitable path between two points.
- Moreover, this algorithm finds its use in networking as well where different routing protocols use it to update or forward data in routing tables.
What Is C++ Dijkstra’s Algorithm? Read Below
The C++ Dijkastra’s Algorithm Algorithm is often termed the Shortest Path Algorithm. As helps to find out the shortest path from the given graph. But before we start briefing about the C++ Dijkstra Algorithm, there is a need to know about the graph in a very small chunk.
A graph is a special Data Structure that is developed with the help of the tree concept. The graph is a non-linear data structure. There are two different components are present. One is the Node & the other is the Edge.
Dijkstra’s Algorithm in C++ is one of the similar operations on the graph. There is a need to start the graph from one of the vertices. And the graph traverses to different vertices based on the values of the edges. You should need to remember that vertices move towards the vertices who has the smallest value of edges.
here are many algorithms. They all have different strategies to sort the giving sequence. Like there is the Quick sort algorithm, Bubble sort algorithm, Heap sort algorithm, etc.
Now, let us see how Dijkstra’s Algorithm in C++ works to find the shortest path and how can we implement it in our C++ code. Keep reading to know!
How Does The Dijkstra Algorithm Works in C++?
Before we start the code implementation of Dijkstra’s Algorithm in C++, let us understand the problem at hand and see what is the actual purpose of using this algorithm. So, what is Dijkstra’s Shortest Path Algorithm?
The Dijkstra Algorithm is needed when we are given a graph and a source vertex and we need to find the shortest path from the source vertex to all the other vertices in that given graph.
Let us define some of the terms we will be using further to grasp the concept completely:
- Source Vertex: The starting node from where the algorithm or traversal begins.
- Destination Vertex: The node which is our target i.e. the node till which the algorithm calculates the shortest path from the source vertex.
- Paths: These represent the routes or distances from the source to the destination node on the graph. They may have varying lengths or distances.
- Weights: Each path on the graph may have a value associated with it that represents the distance or cost of that path.
Now that we have defined the components or elements of Dijkstra’s algorithm, let us see how Dijkstra’s algorithm works.
Step 1: Starting The Traversing:
In the provided graph, there is a need to start from any of the vertices. Here, we are assuming that the starting vertice will be the A node. So, we have marked the A node as the visited one. And the remaining nodes as the unvisited ones. Then we need to move ahead with the help of the shortest path. It will be cleared when the next step will be discussed.
Step 2: Move To Neighbour:
Now, from the A node, there is a need to stare at two of its neighboring nodes. We can see there are two neighbors present. One is the B vertex & the other is the C vertex.
Now, there is a need to look at the value of the edges. The value of the edges helps to find out which vertice is placed near the current vertex. As the edge that connects A with B has the smallest value, then as per the theory of Dijkstra’s Algorithm in C++, we need to move to B and B will be marked as the visited one.
Step 3: Concluding The Process:
Now, B is marked. Also, one of its neighboring vertices is marked as a visited one. It is the A vertex. Now, only one node is left there that is not marked with the visited. It is the C node. Now, there is a need to mark that node as the visited one. And it will be placed on the visited list. As the unvisited list is now empty, then the program needs to be concluded. Hence, we have got the sequence of the nodes based on the shortest path.
This is how we traverse to find the minimum distance in a graph using Dijkstra’s Algorithm.
Did you face any difficulty understanding the above process? Don’t worry, you can get help from reliable C++ programming homework experts and clear all your doubts.
Is Dijkstra a greedy algorithm? Yes, the Dijkstra Algorithm is one of the most used greedy algorithms that we use to solve various problems.
Let us see the algorithm steps below based on the understanding of the above given step-by-step representation.
Steps for Dijkstra Algorithm:
- First, mark all the vertices present in the graph as the unvisited ones. Also, there will be a list of vertices that will be visited with time.
- When the program starts we will take a source vertex that will be marked as visited & will be placed into another part.
- Next, we will find the shortest path in the neighboring vertices by comparing their weights or distances. The node with the smaller value will be marked as visited.
- The same process needs to be followed. Step 4 needs to be executed till all the nodes are marked as visited. There is a need to use the recursion method or a loop to complete the process.
- When all the vertices are marked as visited, there is a need to conclude the program & print the output.
How To Implement The Dijkstra’s Algorithm in C++?
The Dijkstra Algorithm C++ Implementation process is very simple. The process starts from the main function. In the main function, there is a need to take all the edge values as a format in a 2D array. Let us consider the following graph as Dijkstra’s Algorithm example in this case.
Here, we will be finding the shortest paths from the starting vertex A to all the other points.
Let us see the code implementation below.
#include<iostream>
#include <limits.h>
using namespace std;
// Function to find the vertex with the minimum distance value
int minDistance(int dist[], bool Tset[]) {
int min = INT_MAX, min_index;
for (int i = 0; i < 6; i++)
if (Tset[i] == false && dist[i] <= min)
min = dist[i], min_index = i;
return min_index;
}
// Function to print the output
void output(int dist[]) {
cout << "Vertex \t Distance from the Source\n";
for (int i = 0; i < 6; i++){
char ver = 65+i;
cout << ver << " \t\t " << dist[i] << endl;
}
}
void dijkstraAlgorithm(int graph[6][6], int src) {
int dist[6]; // creating a list to store the shortest distances for each vertex
bool Tset[6];
for (int i = 0; i < 6; i++)
dist[i] = INT_MAX, Tset[i] = false;
dist[src] = 0; // this is because the distance from source to source is zero
// Finding shortest paths for each vertex
for (int count = 0; count < 6 - 1; count++) {
int u = minDistance(dist, Tset);
// Mark the vertex as visited
Tset[u] = true;
for (int v = 0; v < 6; v++)
if (!Tset[v] && graph[u][v] && dist[u] != INT_MAX && dist[u] + graph[u][v] < dist[v])
dist[v] = dist[u] + graph[u][v];
}
// Print the output
output(dist);
}
int main()
{
/* Let us create the example graph discussed above */
int graph[6][6] = { { 0, 1, 2, 0, 0, 0},
{ 1, 0, 1, 0, 3, 0},
{ 2, 1, 0, 2, 2, 0},
{ 0, 0, 2, 0, 1, 1},
{ 0, 3, 2, 1, 0, 2},
{ 0, 0, 0, 1, 2, 0},
};
dijkstraAlgorithm(graph, 0);
return 0;
}
In the above code, we see that we have a graph that has six vertices naming from A to F. The weights on these are also mentioned. The whole graph is represented in the main() as graph[6][6]
Now, we pass this graph as an argument to the function dijkstraAlgorithm() that firstly marks all these vertices as unvisited by setting the shortest path tree (Tset) as false.
Then we take up each vertex one by one and start calculating the distance and updating the distance in the array dist. When the whole operation is completed, we print the shortest path from the source of all vertices using the output() function.
Let us try to find out the output of the above code. It will help to know about Dijkastra’s Algorithm C++.
Output:
From the above output, we can see all the shortest paths from vertex A to other vertices in the graph. We see that the distance on vertex A is 0 as it is the source vertex. As we move to the other vertices, we can see how adding the weights on the paths gives us the final shortest distance.
I hope that now you can implement Dijkstra’s Shortest Path Finding Algorithm easily. Let us now see what are the applications of this algorithm in the real world.
What Are The Real-World Applications Of The Dijkstra’s Algorithm?
The different domain uses the same theory to implement different gadgets that help to reduce the work. So, let us try to focus on the following point of application of Dijkastra’s Algorithm C++.
- Dijkastra’s Algorithm C++ is highly used in the computer networking concept to find out the nearest node present that helps to work routers & other internet gadgets.
- This algorithm helps to find out the shortest distance between two locations which helps to develop different map applications in Android or web browsers.
- Dijkastra’s Algorithm C++ helps to find the nearest switching station in the telephonic conversation process that helps to connect one device to another easily.
- This algorithm is used to find out possible hops present in a computer network. And if they are present, it helps to reduce the count in the computer networking.
- Dijkastra’s Algorithm C++ helps to find out the shortest path present in between the handshake method or the connection build-up with the help of that method. Simply, it helps in electronic engineering.
If you’re interested to know more about applications for C++, then you can check out our article “Applications of C++”.
Conclusion:
As we saw Dijkastra’s Algorithm C++ is a very important topic.
There is a need to understand the concept clearly before going through the implementation process. There is a need to clear the theory of the topic to understand the overall process in Dijkastra’s Algorithm C++.
It is advisable to clear the basic concept of the C++ programming language. It will help to understand the implementation process of Dijkastra’s Algorithm C++ more easily. There is a need to clear this concept. As it will help us to solve different difficult problems in the future.
So, hope you have liked this piece of article. Share your thoughts in the comments section and let us know if we can improve more.
Key Takeaways:
- Dijkstra’s Algorithm is one of the algorithms in the group of greedy algorithms.
- These algorithms help us to make the optimal choices at the local or current stage.
- The Dijkstra’s Algorithm works in a graph having positive weights. It is used to calculate the shortest distance between two points.
- The point from where the algorithm starts is the source vertex, and the other point is the destination vertex.
- In C++, the Dijkstra’s Algorithm helps us to find the shortest path from one source to all the other vertices in the graph.
- This algorithm is used in GPS systems, mapping of geological locations, and IP routing.
