do exec

Author: rumycoding

exercises/conversions/as_ref_mut.rs

@@ -7,25 +7,29 @@
 // Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 // Obtain the number of bytes (not characters) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn byte_counter<T>(arg: T) -> usize {
+fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().as_bytes().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn char_counter<T>(arg: T) -> usize {
+fn char_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().chars().count()
 }
 
 // Squares a number using as_mut().
 // TODO: Add the appropriate trait bound.
-fn num_sq<T>(arg: &mut T) {
+fn num_sq<T, U>(arg: &mut T)
+where 
+    T: AsMut<U>,
+    U: std::ops::Mul<Output = U> + Copy,
+{
     // TODO: Implement the function body.
-    ???
+    let inner= arg.as_mut();
+    *inner = (*inner) * (*inner);
 }
 
 #[cfg(test)]

exercises/tests/build.rs

@@ -10,15 +10,13 @@ fn main() {
         .duration_since(std::time::UNIX_EPOCH)
         .unwrap()
         .as_secs(); // What's the use of this timestamp here?
-    let your_command = format!(
-        "Your command here with {}, please checkout exercises/tests/build.rs",
-        timestamp
-    );
-    println!("cargo:{}", your_command);
+    // Tell Cargo to set TEST_FOO for the compiled crate so the
+    // test can read it at runtime.
+    println!("cargo:rustc-env=TEST_FOO={}", timestamp);
 
     // In tests8, we should enable "pass" feature to make the
     // testcase return early. Fill in the command to tell
     // Cargo about that.
-    let your_command = "Your command here, please checkout exercises/tests/build.rs";
+    let your_command = "rustc-cfg=feature=\"pass\"";
     println!("cargo:{}", your_command);
 }

exercises/tests/tests5.rs

@@ -22,7 +22,6 @@
 // Execute `rustlings hint tests5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 /// # Safety
 ///
@@ -32,7 +31,9 @@ unsafe fn modify_by_address(address: usize) {
     // code's behavior and the contract of this function. You may use the
     // comment of the test below as your format reference.
     unsafe {
-        todo!("Your code goes here")
+        // todo!("Your code goes here")
+        let v = address as *mut u32;
+        *v = 0xAABBCCDD;
     }
 }
 

exercises/tests/tests6.rs

@@ -7,8 +7,6 @@
 // Execute `rustlings hint tests6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 struct Foo {
     a: u128,
     b: Option<String>,
@@ -20,8 +18,14 @@ struct Foo {
 unsafe fn raw_pointer_to_box(ptr: *mut Foo) -> Box<Foo> {
     // SAFETY: The `ptr` contains an owned box of `Foo` by contract. We
     // simply reconstruct the box from that pointer.
-    let mut ret: Box<Foo> = unsafe { ??? };
-    todo!("The rest of the code goes here")
+    let mut ret: Box<Foo> = unsafe { 
+        (*ptr).b =Some("hello".to_string());
+
+        Box::from_raw(ptr) 
+    };
+
+    ret
+    // todo!("The rest of the code goes here")
 }
 
 #[cfg(test)]

exercises/tests/tests7.rs

@@ -34,7 +34,6 @@
 // Execute `rustlings hint tests7` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {}
 

exercises/tests/tests8.rs

@@ -7,8 +7,6 @@
 // Execute `rustlings hint tests8` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {}
 
 #[cfg(test)]

exercises/tests/tests9.rs

@@ -27,15 +27,16 @@
 //
 // You should NOT modify any existing code except for adding two lines of attributes.
 
-// I AM NOT DONE
 
 extern "Rust" {
     fn my_demo_function(a: u32) -> u32;
+    #[link_name = "my_demo_function"]
     fn my_demo_function_alias(a: u32) -> u32;
 }
 
 mod Foo {
     // No `extern` equals `extern "Rust"`.
+    #[no_mangle]
     fn my_demo_function(a: u32) -> u32 {
         a
     }