diff --git a/docs/docs.md b/docs/docs.md
index 37f5fac..0f7da59 100644
--- a/docs/docs.md
+++ b/docs/docs.md
@@ -204,11 +204,11 @@ Variable arguments can be accessed using the built-in variables `argv` and `argc
 
 func add_nums(...) i32 {
     let n i32 = 0;
-    let idx i32 = 0;
+    let i i32 = 0;
 
-    while idx < argc {
-        n = n + argv[idx];
-        idx++;
+    while i < argc {
+        n = n + argv[i];
+        i++;
     }
 
     return n;
diff --git a/docs/docs_jp.md b/docs/docs_jp.md
index 1117082..3f16c8f 100644
--- a/docs/docs_jp.md
+++ b/docs/docs_jp.md
@@ -205,11 +205,11 @@ label:
 
 func add_nums(...) i32 {
     let n i32 = 0;
-    let idx i32 = 0;
+    let i i32 = 0;
 
-    while idx < argc {
-        n = n + argv[idx];
-        idx++;
+    while i < argc {
+        n = n + argv[i];
+        i++;
     }
 
     return n;