Merge pull request #217 from TheAlgorithms/add_prime_factoriziation

Prime factoriziation

misc/PrimeFactoriziation.c

@@ -0,0 +1,172 @@
+/*
+    AUTHOR: Christian Bender
+    DATE: 12.02.2019
+    DESCRIPTION: This program calculates the prim factoriziation of a positive integer > 1
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+/* initial length of the dynamic array */
+#define LEN 10
+
+/* increasing range */
+#define STEP 5
+
+/*
+    this type is for the representation of the prim factoriziation
+    - its series/range of prim factors
+    - its length : numbers of prim factors
+*/
+typedef struct data
+{
+    int * range;
+    int length;
+} range;
+typedef range* Range;
+
+/* int_fac : calculates the prim factoriziation of positive integers */
+Range int_fact(int);
+
+/* print_arr : prints the integer (heap) array*/
+void print_arr(Range);
+
+/* increase : increases the dynamic integer array */
+int * increase(int *, int);
+
+/* destroy: destroys the range-structure */
+void destroy(Range);
+
+/*
+    main : simle frame program with a simple UI
+*/
+int main()
+{
+
+    int n = 0; /* for user input */
+
+    printf("\t\tPrim factoriziation\n\n");
+    printf("positive integer (> 1) ? ");
+    scanf("%d", &n);
+    Range r = int_fact(n);
+    printf("\nThe factoriziation are: ");
+    print_arr(r);
+    destroy(r);
+    return 0;
+}
+
+
+Range int_fact(int n)
+{
+    assert(n > 1); /* precondition : n must be greater then 1*/
+
+    int len = LEN;
+    int count = 0;
+    int i = 0;
+    int * range = (int *) malloc(sizeof(int) * len);
+    assert(range);
+    Range pstr = (Range) malloc(sizeof(range));
+    assert(pstr);
+
+    while (n % 2 == 0)
+    {
+        n /= 2;
+        if (i < len)
+        {
+            range[i] = 2;
+            i++;
+        }
+        else
+        {
+            range = increase(range, len);
+            len += STEP;
+            range[i] = 2;
+            i++;
+        }
+        count++;
+
+    }
+
+    int j = 3;
+    while (j*j <= n)
+    {
+        while (n % j == 0)
+        {
+            n /= j;
+            if (i < len)
+            {
+                range[i] = j;
+                i++;
+            }
+            else
+            {
+                range = increase(range, len);
+                len += STEP;
+                range[i] = j;
+                i++;
+            }
+            count++;
+        }
+
+        j += 2;
+    }
+
+
+    if (n > 1)
+    {
+        if (i < len)
+        {
+            range[i] = n;
+            i++;
+        }
+        else
+        {
+            range = increase(range, len);
+            len += STEP;
+            range[i] = n;
+            i++;
+        }
+        count++;
+    }
+
+    pstr->range = range;
+    pstr->length = count;
+    return pstr;
+
+
+}
+
+
+void print_arr(Range pStr)
+{
+    assert(pStr); /* checks whether pStr is a null-pointer */
+    int i = 0;
+    printf("\n");
+    for (i; i < pStr->length; i++)
+    {
+        if (i == 0)
+            printf("%d", pStr->range[0]);
+        else
+            printf("-%d", pStr->range[i]);
+    }
+    printf("\n");
+}
+
+
+int * increase(int * arr, int len)
+{
+    assert(arr); /* checks whether arr is a null-pointer */
+    int * tmp = (int*) realloc(arr, sizeof(int) * (len + STEP));
+    assert(tmp);
+    return tmp;
+//    assert(arr);
+}
+
+
+void destroy(Range r)
+{
+    free(r->range);
+    free(r);
+}