1 files changed, 6 insertions, 4 deletions

diff --git a/src/ppm.c b/src/ppm.c
index a5cf3fe..a868b76 100644
--- a/src/ppm.c
+++ b/src/ppm.c
@@ -9,7 +9,8 @@ ppm_write(const char *file, Image *img)
     /*
      * Write a ppm file
      */
-    FILE *fp = fopen(file, "w");
+    FILE *fp;
+    fp = (file) ? fopen(file, "r") : stdout;
 
     if (fp == NULL) {
         perror("ppm_read() Error");
@@ -20,7 +21,7 @@ ppm_write(const char *file, Image *img)
 
     fprintf(fp, "P6\n%d %d\n%d\n", img->width, img->height, img->pixel_bits);
     fwrite(img->data, n_pixels, sizeof(uint8_t), fp);
-    fclose(fp);
+    if (fp != stdout) fclose(fp);
 }
 
 void
@@ -29,7 +30,8 @@ ppm_read(const char *file, Image *img)
      * Read a ppm file
      */
 {
-    FILE *fp = fopen(file, "r");
+    FILE *fp;
+    fp = (file) ? fopen(file, "r") : stdin;
 
     if (fp == NULL) {
         perror("ppm_read() Error");
@@ -50,7 +52,7 @@ ppm_read(const char *file, Image *img)
         fclose(fp);
         exit(1);
     }
-    fclose(fp);
+    if (fp != stdin) fclose(fp);
 }
 
 void