rustlab

basics- part 1

$ rustup.sh       # install rust, see rust-lang.org for details
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh


$ cargo new bin   # start new executable project
$ ls -lR          # list our skeleton of files
src/main.rs       # main.rs, has main() entry point
Cargo.toml        # Cargo.toml defines packaging
$ $EDITOR Cargo.toml  # add dependencies and other details
[package]
name = "helloworld"
version = "0.1.0"
authors = ["rustlabs <[email protected]>"]

[dependencies]
serde = "1.0.80"

$ cargo build     # downloads dependencies + builds main.rs 
$ cargo run       # runs program created from main.rs
$ cargo test      # runs tests (in parallel by default)
$ cargo test -- --test-threads=1  # run tests one at a time
$ cargo test -- --nocapture       # run tests, show output

world famous hello world
```
fn main() {
    println!("Hello, world!");
}

```
variable and placeholder 
```
fn main() { 
    let name ="sangam" ;
    println!("Hello, {} ",name); 
    }
```
refine varible 2 times 
```
fn main() {
   let name = "sangam";
    println!("Hello, {}", name);
  name = "biradar";
   println!("Hello, {}", name);    
  }

  ```

  ```

fn main() {
   let mut name = "Sangam";
   println!("Hello, {}", name);
   name = "Rust";
   println!("Hello, {}", name);
}



  ```


  ```
fn main() {
    println!("{}, {}!", "Hello", "world"); // Hello, world!
    println!("{0}, {1}!", "Hello", "world"); // Hello, world!
    println!("{greeting}, {name}!", greeting="Hello", name="world"); // Hello, world!

    println!("{:?}", [1,2,3]); // [1, 2, 3]
    println!("{:#?}", [1,2,3]);
    /*
        [
            1,
            2,
            3
        ]
    */

    // 🔎 The format! macro is used to store the formatted string.
    let x = format!("{}, {}!", "Hello", "world");
    println!("{}", x); // Hello, world!

    // 💡 Rust has a print!() macro as well
    print!("Hello, world!"); // Without new line
    println!(); // A new line

    print!("Hello, world!\n"); // With new line
}





  ````

  ```
fn add(a: i32, b: i32) -> i32 {
    a + b
}

 fn main() {
    println!("1 + 1 = {}", add(1, 1));
    println!("13 + 23 = {}", add(13, 23));
}

  ```

  ```
fn add(a: i32, b: i32) -> i32 {
    let answer: i32;
    answer = a + b;
    answer
}

fn main() {
    println!("1 + 1 = {}", add(1, 1));
    println!("13 + 23 = {}", add(13, 23));
}



  ```

  ```

fn add(a: i32, b: i32) -> i32 {
    a + b
}
fn sub(a: i32, b: i32) -> i32 {
    return a - b;
}
fn main() {
    println!("1 + 1 = {}", add(1, 1));
    println!("13 + 23 = {}", add(13, 23));
     println!("23 - 13 = {}", sub(23, 13));
}

array 

```
let a = [1, 2, 3];                  // a: [i32; 3] 
let mut m = [1, 2, 3];      // m: [i32; 3]

 fn main() {
    let a = [1, 2, 3];
    println!("0th element {}", a[0]);
    println!("1th element : {}", a[1]);
    println!("2th element: {}", a[2]);
}

```

length of array 
  ```

fn main() {
    let a  = [1, 2, 3,4];
 println!("# of items in a: {}", a.len());
}
```


```
fn main(){
    let x = 5;
    if x > 10 {
        println!("x > 10")
    }else if x > 0{
        println!("x < x <= 10")  
    }else{
        println!("x < 0")
    };
}



```

if is a expression, not statement in Rust So, it has an evaluation value

```


fn main(){
    let x = 5;
    let y = if x > 0{
        1
    }else{ 
        0
    };
    println!("y = {}", y);  
}



```
loop statement 
```

fn main() {
    let mut i = 0;
    loop{
        i = i +1;
        println!("{} sangam biradar ", i);
        if i > 9{
            break;
        }
    }
}

```
for loop range 


```
fn main() {
    for x in 0..10 {
        println!("{}", x); // x: i32
    }
    }


```