#include <stdio.h>
// Función para fusionar dos subarreglos ordenados en un solo arreglo
void merge(int arr[], int l, int m, int r) {
    int i, j, k;
    int n1 = m - l + 1;
    int n2 = r - m;
    // Crear arreglos temporales
    int L[n1], R[n2];
    // Copiar datos a los arreglos temporales L[] y R[]
    for (i = 0; i < n1; i++)
        L[i] = arr[l + i];
    for (j = 0; j < n2; j++)
        R[j] = arr[m + 1 + j];
    // Fusionar los arreglos temporales en el arreglo original
    i = 0; // Índice inicial del primer subarreglo
    j = 0; // Índice inicial del segundo subarreglo
    k = l; // Índice inicial del subarreglo fusionado
    while (i < n1 && j < n2) {
        if (L[i] <= R[j]) {
            arr[k] = L[i];
            i++;
        }
        else {
            arr[k] = R[j];
            j++;
        }
        k++;
    }
    // Copiar los elementos restantes de L[] si los hay
    while (i < n1) {
        arr[k] = L[i];
        i++;
        k++;
    }
    // Copiar los elementos restantes de R[] si los hay
    while (j < n2) {
        arr[k] = R[j];
        j++;
        k++;
    }
}
// Función recursiva para dividir y ordenar el arreglo
void mergeSort(int arr[], int l, int r) {
    if (l < r) {
        // Encuentra el punto medio del arreglo
        int m = l + (r - l) / 2;
        // Ordena la primera mitad y la segunda mitad recursivamente
        mergeSort(arr, l, m);
        mergeSort(arr, m + 1, r);
        // Combina las dos mitades ordenadas
        merge(arr, l, m, r);
    }
}
// Función para imprimir el arreglo
void printArray(int A[], int size) {
    for (int i = 0; i < size; i++)
        printf("%d ", A[i]);
    printf("\n");
}
int main() {// Programa principal
    int arr[] = {1, 8, 7, 5, 6, 3, 2, 4};
    int arr_size = sizeof(arr) / sizeof(arr[0]);
    printf("Arreglo original:\n");
    printArray(arr, arr_size);
    mergeSort(arr, 0, arr_size - 1);
    printf("\nArreglo ordenado usando Merge Sort:\n");
    printArray(arr, arr_size);
    return 0;
}
 
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#include <stdio.h>
int main()
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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
}