#include <stdlib.h>
#include <string.h>
#include <stdio.h>
int comparator(const void* p1, const void* p2) { 
    const int(*x)[3] = p1; 
    const int(*y)[3] = p2; 
    return (*x)[2] - (*y)[2]; 
} 


void makeSet(int parent[], int rank[], int n) 
{ 
    for (int i = 0; i < n; i++) {
        parent[i] = i; 
        rank[i] = 0; 
    } 
} 

int findParent(int parent[], int comp) 
{ 
    if (parent[comp] == comp) 
        return comp; 
  
    return parent[comp] = findParent(parent, parent[comp]); 
} 


void unionSet(int u, int v, int parent[], int rank[], int n) { 
    u = findParent(parent, u); 
    v = findParent(parent, v); 
  
    if (rank[u] < rank[v]) { 
        parent[u] = v; 
    } 
    else if (rank[u] > rank[v]) { 
        parent[v] = u; 
    } 
    else { 
        parent[v] = u; 
        rank[u]++; 
    } 
} 

void kruskalAlgo(int n ,int edge[n][3]){
   qsort(edge, n, sizeof(edge[0]), comparator); 
    int parent[n]; 
    int rank[n]; 
      makeSet(parent, rank, n); 
      int minCost=0;
      
    printf( 
        "Following are the edges in the constructed MST\n"); 
    for (int i = 0; i < n; i++) { 
        int v1 = findParent(parent, edge[i][0]); 
        int v2 = findParent(parent, edge[i][1]); 
        int wt = edge[i][2]; 
        if (v1 != v2) { 
            unionSet(v1, v2, parent, rank, n); 
            minCost += wt; 
            printf("%d->%d = %d\n", edge[i][0], 
                   edge[i][1], wt); 
        } 
    }
    
    printf("Minimum Cost Spanning Tree: %d\n", minCost); 
}
int main() 
{ 
    int edge[5][3] = { { 0, 1, 10 }, 
                       { 0, 2, 6 }, 
                       { 0, 3, 5 }, 
                       { 1, 3, 15 }, 
                       { 2, 3, 4 } }; 
  
    kruskalAlgo(5, edge); 
    return 0; 
}

C Language online compiler

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Read inputs from stdin

OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.

#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

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
}