diff --git a/.gitignore b/.gitignore
index 9986867..ac98f20 100644
--- a/.gitignore
+++ b/.gitignore
@@ -62,3 +62,5 @@ build
 CMakeCache.txt
 Makefile
 src/huffman/testfiles
+data
+cmake_install.cmake
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e499e29..ecfdd44 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,7 @@ add_executable( echochar                src/echochar.c              )
 add_executable( euler                   src/euler.c                 )
 add_executable( factorial               src/factorial.c             )
 add_executable( fail                    src/fail.c                  )
+add_executable( fib                    	src/fib.c                  	)
 add_executable( fread                   src/fread.c                 )
 add_executable( hello-world             src/hello-world.c           )
 add_executable( options                 src/options.c               )
diff --git a/src/euler.c b/src/euler.c
index 30272da..07f0a7b 100644
--- a/src/euler.c
+++ b/src/euler.c
@@ -20,7 +20,7 @@ double factorial(double i) {
 
     // someone said i need 2 for loops. Totally wrong?
     for(int j=1;j<given;j++){
-        
+
         p *= j;
         //printf("[DEBUG]p is %f, j is %d\n", p, j);
     }
@@ -35,16 +35,15 @@ int main(int argc, char *argv[]){
     int k = 0;
     int end = 0;
     while(!end){
-	res += euler(k);
-	printf("%f, %f\n", res, lres);
-	if(res==lres)
-	    end = 1;
-	else { 
-	    lres = res;
-	}
-	k++;
+        res += euler(k);
+        printf("%f, %f\n", res, lres);
+        if(res==lres)
+            end = 1;
+        else {
+            lres = res;
+        }
+        k++;
     }
     printf("calculated eulers number as %f\n", res);
     return 0;
 }
-
diff --git a/src/fib.c b/src/fib.c
new file mode 100644
index 0000000..6f42c11
--- /dev/null
+++ b/src/fib.c
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <inttypes.h>
+
+const int START_VALUES[2] = {0, 1};
+const int LIMIT = 90;
+
+int main(int argc, char** argv) {
+	if (argc != 2) {
+		printf("usage: %s MAX_NUMBER\n", argv[0]);
+		exit(1);
+	}
+	int max = atoi(argv[1]);
+	if (max > LIMIT) {
+		printf("C does not provide a datatype large enough to compute fibonacci numbers > %d. (%d)\n", LIMIT, max);
+		exit(1);
+	}
+	uintmax_t* nums = malloc(max * sizeof(uintmax_t));
+	nums[0] = START_VALUES[0];
+	nums[1] = START_VALUES[1];
+
+	for(int i = 2; i < max+1; i++) {
+		nums[i] = nums[i-2] + nums[i-1];
+	}
+
+	for(int i = 0; i < max+1; i++) {
+		printf("%02d. %ju\n", i, nums[i]);
+	}
+}
diff --git a/src/miniio.c b/src/miniio.c
index 6f1aa5e..0dadd8d 100644
--- a/src/miniio.c
+++ b/src/miniio.c
@@ -2,9 +2,9 @@
 #include <string.h>
 
 int my_strlen(const char *s) {
-  int len = 0;
-  while (s[len] != 0) {
-      len++;
+  register int len = 0; // try to use a register instead of a stack variable
+  while (s[len]) {
+    len++;
   }
   return len;
 }
diff --git a/src/readfile.c b/src/readfile.c
index fb5f773..ad56c6f 100644
--- a/src/readfile.c
+++ b/src/readfile.c
@@ -1,9 +1,13 @@
 #include <stdlib.h>
 #include <stdio.h>
  
-int main(void)
+int main(int argc, char** argv)
 {
-   char filename[] = "file.txt";
+   if (argc != 2) {
+      printf("usage: %s FILE", argv[0]);
+      exit(1);
+   }
+   char* filename = argv[1];
    char buf[2];
    FILE *fp;