Try to clarify different aspects of for loops.

website/versioned_docs/version-0.14/01-language-basics/05-for-loops.mdx

@@ -1,12 +1,22 @@
 import CodeBlock from "@theme/CodeBlock";
 
 import For from "!!raw-loader!./05.for.zig";
+import ForIndex from "!!raw-loader!./05.for-index.zig";
+import ForMultipleIterables from "!!raw-loader!./05.for-multiple-iterables.zig";
 
 # For loops
 
 For loops are used to iterate over arrays (and other types, to be discussed
-later). For loops follow this syntax. Like while, for loops can use `break` and
-`continue`. Here, we've had to assign values to `_`, as Zig does not allow us to
-have unused values.
+later). Like while, for loops can use `break` and `continue`.
 
 <CodeBlock language="zig">{For}</CodeBlock>
+
+Iterating over multiple arrays is possible using a single for loop, as long as
+all arrays are the same size.
+
+<CodeBlock language="zig">{ForMultipleIterables}</CodeBlock>
+
+To extract the index while iterating, use `0..` to indicate an unbounded range
+starting at zero.
+
+<CodeBlock language="zig">{ForIndex}</CodeBlock>

website/versioned_docs/version-0.14/01-language-basics/05.for-index.zig

@@ -0,0 +1,15 @@
+// hide-start
+const expect = @import("std").testing.expect;
+
+// hide-end
+test "for" {
+    const vals = [4]u8{ 10, 20, 30, 40 };
+    var val_sum: u32 = 0;
+    var index_sum: usize = 0;
+    for (vals, 0..) |num, index| {
+        val_sum += num;
+        index_sum += index;
+    }
+    try expect(index_sum == 6);
+    try expect(val_sum == 100);
+}

website/versioned_docs/version-0.14/01-language-basics/05.for-multiple-iterables.zig

@@ -0,0 +1,13 @@
+// hide-start
+const expect = @import("std").testing.expect;
+
+// hide-end
+test "for loop with multiple iterables" {
+    var sum: i32 = 0;
+    const digits = [4]i32{ 7, 3, 4, 9 };
+    const places = [4]i32{ 1, 10, 100, 1000 };
+    for (digits, places) |digit, place| {
+        sum += digit * place;
+    }
+    try expect(sum == 9437);
+}

website/versioned_docs/version-0.14/01-language-basics/05.for.zig

@@ -3,21 +3,21 @@ const expect = @import("std").testing.expect;
 
 // hide-end
 test "for" {
-    //character literals are equivalent to integer literals
-    const string = [_]u8{ 'a', 'b', 'c' };
-
-    for (string, 0..) |character, index| {
-        _ = character;
-        _ = index;
-    }
-
-    for (string) |character| {
-        _ = character;
+    const vals = [_]u8{ 2, 3, 4 };
+    var sum: u8 = 0;
+    // num is the captured value on each iteration of the loop.
+    for (vals) |num| {
+        sum += num;
     }
+    try expect(sum == 9);
+}
 
-    for (string, 0..) |_, index| {
-        _ = index;
+test "for-with-continue" {
+    const vals = [_]u8{ 2, 3, 0, 4 };
+    var product: u32 = 1;
+    for (vals) |num| {
+        if (num == 0) continue;
+        product *= num;
     }
-
-    for (string) |_| {}
+    try expect(product == 24);
 }