diff --git a/entropy.c b/entropy.c
index 7b0244e..fb45c9c 100644
--- a/entropy.c
+++ b/entropy.c
@@ -7,6 +7,7 @@ main(int argc, char *argv[])
 	size_t len = 0;
 	size_t hist[256] = {0};
 	int c;
+    int i;
 
 	while ((c = getchar()) != EOF) {
 		hist[c] += 1;
@@ -14,7 +15,7 @@ main(int argc, char *argv[])
 	}
 
 	float H = 0;
-	for (int i = 0; i < 256; i += 1) {
+	for (i = 0; i < 256; i += 1) {
 		if (hist[i]) {
 			float Hi = (float)hist[i]/len;
 			H -= Hi * log2(Hi);