#include <stdio.h>
#include <stdlib.h>
#define MAX_VERTICES 100

int G[MAX_VERTICES][MAX_VERTICES];
int n;

int vertex(int dist[], int visited[]) {
    int min = 999, a;
    for(int i = 0; i < n; i++) {
        if(dist[i] < min && visited[i] == 0) {
            min = dist[i];
            a = i;
        }
    }
    return a;
}

void display(int dist[]) {
    printf("\nVertex \t Distance from Source:\n");
    for(int i = 0; i < n; i++)
        printf("%d\t%d\n", i, dist[i]);
}

void dj(int G[][MAX_VERTICES]) {
    int s;
    printf("\nEnter starting vertex : ");
    scanf("%d", &s);
    int dist[MAX_VERTICES], visited[MAX_VERTICES];
    for (int i = 0; i < n; i++) {
        dist[i] = 999;
        visited[i] = 0;
    }
    dist[s] = 0;
    for (int i = 0; i < n; i++) {
        int u = vertex(dist, visited);
        visited[u] = 1;
        for (int j = 0; j < n; j++) {
            if (visited[j] != 1 && G[u][j] && dist[u] != 999 && dist[u] + G[u][j] < dist[j])
                dist[j] = dist[u] + G[u][j];
        }
    }
    display(dist);
}

void matrix() {
    int e, a, b, w;
    printf("\nEnter the no of vertex : ");
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            G[i][j] = 999;
        }
    }
    printf("\nEnter the no of edges : ");
    scanf("%d", &e);
    for (int i = 0; i < e; i++) {
        printf("\nEnter edge : ");
        scanf("%d %d", &a, &b);
        printf("\nEnter weight from edge %d to %d : ", a, b);
        scanf("%d", &w);
        G[a][b] = G[b][a] = w;
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            printf("%5d ", G[i][j]);
        }
        printf("\n");
    }
}

int main() {
    int m;
    while (1) {
        printf("\n\n\t** MST Using Kruskal using Adjacency list and Matrix.");
        printf("\n1. Dijkstras Algorithm using matrix \n2. Dijkstras using Adjacency List \n3. Exit\n");
        printf("\nEnter which algorithm : ");
        scanf("%d", &m);
        switch (m) {
            case 1:
                matrix();
                dj(G);
                break;
            case 2:
                exit(0);
            default:
                printf("\nEnter a valid option.");
        }
    }
    return 0;
}
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    return 0;
    
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About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}