3 files changed, 21 insertions, 18 deletions
diff --git a/src/main.c b/src/main.c
deleted file mode 100644
index 6bb704a..0000000
--- a/src/main.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "lizfcm.h"
-#include <stdio.h>
-
-int main() {
-  printf("hello, from lizfcm!\n");
-  return 0;
-}
diff --git a/src/matrix.c b/src/matrix.c
index a23aad4..953d50f 100644
--- a/src/matrix.c
+++ b/src/matrix.c
@@ -1,5 +1,6 @@
 #include "lizfcm.h"
 #include <assert.h>
+#include <string.h>
 #include <stdio.h>
 
 void put_identity_diagonal(Matrix_double *m) {
@@ -69,14 +70,15 @@ void free_matrix(Matrix_double *m) {
 }
 
 void format_matrix_into(Matrix_double *m, char *s) {
-  sprintf(s, "");
   if (m->rows == 0)
-    sprintf(s, "empty");
+    strcpy(s, "empty");
 
   for (size_t y = 0; y < m->rows; ++y) {
-    char *row_s = malloc(sizeof(char) * 256);
+    char row_s[256];
+    strcpy(row_s, "");
+
     format_vector_into(m->data[y], row_s);
-    sprintf(s, "%s %s \n", s, row_s);
-    free(row_s);
+    strcat(s, row_s);
   }
+  strcat(s, "\n");
 }
diff --git a/src/vector.c b/src/vector.c
index e6e2544..a7ff783 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -2,6 +2,7 @@
 #include <assert.h>
 #include <float.h>
 #include <math.h>
+#include <string.h>
 #include <stdio.h>
 
 double l2_norm(Array_double *v) {
@@ -100,10 +101,17 @@ void free_vector(Array_double *v) {
 }
 
 void format_vector_into(Array_double *v, char *s) {
-  sprintf(s, "");
-  if (v->size == 0)
-    sprintf(s, "empty");
-
-  for (size_t i = 0; i < v->size; ++i)
-    sprintf(s, "%s %f,", s, v->data[i]);
+  if (v->size == 0) {
+    strcat(s, "empty");
+    return;
+  }
+
+  for (size_t i = 0; i < v->size; ++i) {
+    char num[64];
+    strcpy(num, "");
+
+    sprintf(num, "%f,", v->data[i]);
+    strcat(s, num);
+  }
+  strcat(s, "\n");
 }