add format

single_file_tests/format.rs

@@ -0,0 +1,11 @@
+
+fn main() {
+    let a = 1111111;
+
+    println!("{}", a);
+    println!("pointer: {:p}", &a);
+    println!("binary: {:b}", a);
+    println!("octet: {:o}", a);
+    println!("0x{:x}", a);
+    println!("0x{:X}", a);
+}