Implement merge sort in C #91

C++/MergeSort.c

@@ -0,0 +1,81 @@
+#include <stdio.h>  
+
+/* Function to merge the subarrays of a[] */  
+void merge(int a[], int beg, int mid, int end)    
+{    
+    int i, j, k;  
+    int n1 = mid - beg + 1;    
+    int n2 = end - mid;    
+
+    int LeftArray[n1], RightArray[n2]; //temporary arrays  
+
+    /* copy data to temp arrays */  
+    for (int i = 0; i < n1; i++)    
+    LeftArray[i] = a[beg + i];    
+    for (int j = 0; j < n2; j++)    
+    RightArray[j] = a[mid + 1 + j];    
+
+    i = 0; /* initial index of first sub-array */  
+    j = 0; /* initial index of second sub-array */   
+    k = beg;  /* initial index of merged sub-array */  
+
+    while (i < n1 && j < n2)    
+    {    
+        if(LeftArray[i] <= RightArray[j])    
+        {    
+            a[k] = LeftArray[i];    
+            i++;    
+        }    
+        else    
+        {    
+            a[k] = RightArray[j];    
+            j++;    
+        }    
+        k++;    
+    }    
+    while (i<n1)    
+    {    
+        a[k] = LeftArray[i];    
+        i++;    
+        k++;    
+    }    
+
+    while (j<n2)    
+    {    
+        a[k] = RightArray[j];    
+        j++;    
+        k++;    
+    }    
+}    
+
+void mergeSort(int a[], int beg, int end)  
+{  
+    if (beg < end)   
+    {  
+        int mid = (beg + end) / 2;  
+        mergeSort(a, beg, mid);  
+        mergeSort(a, mid + 1, end);  
+        merge(a, beg, mid, end);  
+    }  
+}  
+
+/* Function to print the array */  
+void printArray(int a[], int n)  
+{  
+    int i;  
+    for (i = 0; i < n; i++)  
+        printf("%d ", a[i]);  
+    printf("\n");  
+}  
+
+int main()  
+{  
+    int a[] = { 12, 31, 25, 8, 32, 17, 40, 42 };  
+    int n = sizeof(a) / sizeof(a[0]);  
+    printf("Before sorting array elements are - \n");  
+    printArray(a, n);  
+    mergeSort(a, 0, n - 1);  
+    printf("After sorting array elements are - \n");  
+    printArray(a, n);  
+    return 0;  
+}