Revert "finished first batch"

This reverts commit 455cae6f2875f160508162525b0283de0098ef39.

exercises/intro/intro1.rs

@@ -5,6 +5,8 @@
 // ready for the next exercise, remove the `I AM NOT DONE` comment below.
 // Execute the command `rustlings hint intro1` for a hint.
 
+// I AM NOT DONE
+
 fn main() {
     println!("Hello and");
     println!(r#"       welcome to...                      "#);

exercises/intro/intro2.rs

@@ -2,6 +2,8 @@
 // Make the code print a greeting to the world.
 // Execute `rustlings hint intro2` for a hint.
 
+// I AM NOT DONE
+
 fn main() {
-    println!("Hello World!");
+    println!("Hello {}!");
 }

exercises/variables/variables1.rs

@@ -2,7 +2,9 @@
 // Make me compile!
 // Execute the command `rustlings hint variables1` if you want a hint :)
 
+// I AM NOT DONE
+
 fn main() {
-    let x = 5;
+    x = 5;
     println!("x has the value {}", x);
 }

exercises/variables/variables2.rs

@@ -1,8 +1,10 @@
 // variables2.rs
 // Make me compile! Execute the command `rustlings hint variables2` if you want a hint :)
 
+// I AM NOT DONE
+
 fn main() {
-    let x: u8 = 10;
+    let x;
     if x == 10 {
         println!("Ten!");
     } else {

exercises/variables/variables3.rs

@@ -1,8 +1,10 @@
 // variables3.rs
 // Make me compile! Execute the command `rustlings hint variables3` if you want a hint :)
 
+// I AM NOT DONE
+
 fn main() {
-    let mut x = 3;
+    let x = 3;
     println!("Number {}", x);
     x = 5; // don't change this line
     println!("Number {}", x);

exercises/variables/variables4.rs

@@ -1,7 +1,9 @@
 // variables4.rs
 // Make me compile! Execute the command `rustlings hint variables4` if you want a hint :)
 
+// I AM NOT DONE
+
 fn main() {
-    let x: i32 = 1;
+    let x: i32;
     println!("Number {}", x);
 }

exercises/variables/variables5.rs

@@ -1,9 +1,11 @@
 // variables5.rs
 // Make me compile! Execute the command `rustlings hint variables5` if you want a hint :)
 
+// I AM NOT DONE
+
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    let new_number = 3;
-    println!("Number plus two is : {}", new_number + 2);
+    number = 3;
+    println!("Number plus two is : {}", number + 2);
 }

exercises/variables/variables6.rs

@@ -1,7 +1,9 @@
 // variables6.rs
 // Make me compile! Execute the command `rustlings hint variables6` if you want a hint :)
 
-const NUMBER: i32 = 3;
+// I AM NOT DONE
+
+const NUMBER = 3;
 fn main() {
     println!("Number {}", NUMBER);
 }