1 files changed, 66 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/ifactor.c b/reference/C/CONTRIB/SNIP/ifactor.c
new file mode 100755
index 0000000..900c57a
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/ifactor.c
@@ -0,0 +1,66 @@
+/*
+** ifactor.c -- print prime factorization of a number
+**
+** Ray Gardner -- 1985 -- public domain
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int prevfact = 0;
+void factor (long);
+void show (long, int);
+
+void main (int argc, char *argv[])
+{
+   while ( --argc )
+         factor(atol(*++argv));
+}
+
+void factor (long n)
+{
+      long d;
+      int k;
+      long n0 = n;
+      prevfact = 0;
+
+      printf("%ld  ",n);
+      if ( n < 2 )
+      {
+            printf("is less than 2.\n");
+            return;
+      }
+      else if ( n > 2 )
+      {
+            d = 2;
+            for ( k = 0; n % d == 0; k++ )
+                  n /= d;
+            if ( k )
+                  show(d,k);
+            for ( d = 3; d * d <= n; d += 2 )
+            { 
+                  for ( k = 0; n % d == 0; k++ )
+                        n /= d;
+                  if ( k )
+                        show(d,k);
+            }
+      }
+      if ( n > 1 )
+      {
+            if ( n == n0 )
+                  printf(" is prime");
+            else  show(n,1);
+      }
+      printf("\n");
+}
+
+void show (long d, int k)
+{
+      if ( prevfact )
+            printf(" * ");
+      else  printf(" = ");
+      prevfact++;
+      printf("%ld",d);
+      if ( k > 1 )
+            printf("^%d",k);
+}