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Rust usize

Rust usize

Introduction to Rust usize

It is a primitive type of rust, which is based on pointer like C programming language. If we have a type that does not have a definite size, we call those primitive types as ‘usize’ in rust or dynamically sized types in rust. It is representing as the pointer sized unsigned type in rust. If we want to know about the size of this type, we can refer to how many bytes it takes to represent any of the memory locations. This cannot be predicted at the compile time; this can only be done at the runtime because it does not know how many bite or bytes it will take because is also termed as dynamic size integer. In the coming section, we will discuss more the usize in rust how they work and how they should be implemented in the program in detail.

Syntax

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As we already discuss that usize is used to represent the integer value of the variable. Let’s take a look at its syntax how to define using in Rust for better understanding for beginners see below;

let variable_name:usize = integer_value;

As you can see in the above lines of syntax, we are declaring the usize variable; for this, we are defining a variable by using the type using in rust. let’s take a practice syntax for better understanding for beginners see below;

Example:

let demo:usize = 10;

Just simply assign the value to the usize variable here; in the coming section, we will discuss the internal working of the usize type in rust; this will help beginners see this while programming efficiently for better usage.

How usize function works in Rust?

usize is the type of Unsigned integers in rust; they meant to deal with integers in rust. Also, they allow positive integers only. we have several types available for unsigned integers, out of which usize is one of them, it stores the integer, or we can say its size in the form of an arch. That simply means the size of the type is going to determine by the architecture of the machine. This means we can say dynamic sized type. Let’s discuss the various type of unsigned integer in detail for better understanding see below;

1. usize: The size of the usize is determine by the arch size; it is a pointer based type integer. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:usize = 10;

2. u8: This unsigned integer type size stands for 8 bit. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:u8 = 10;

3. u16: This unsigned integer type size stands for 16 bit. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:u16 = 10;

4. u32: This unsigned integer type size stands for 32 bit. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:u32 = 10;

5. u64: This unsigned integer type size stands for 64 bit. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:u64 = 10;

6. u128: This unsigned integer type size stands for 128 bit. Below we can see the syntax to define and use them while programming in rust see below;

Example:

let demo:u128 = 10;

We have several constant and operations for usize type in rust; let us discuss each of them in detail for better understating and implementation while using them inside the code see below;

a. MIN: This constant is used to represent the smallest value that a using integer can represent. Below we will see its syntax to see its implementation see;

Example:

assert_eq!(usize::MIN, your_value);

b. MAX: This constant is used to represent the maximum value that a usize integer can represent. Below we will see its syntax to see its implementation see;

Example:

assert_eq!(usize::MAX, your_value);

c. min_value(): This operation can be used to return the minimum value that can represent by the integer. Below, we will see its syntax to see its implementation see below;

Example:

(usize::min_value(), 0);

d. maz_value(): This operation can be used to return the maximum value that can represent by the integer. Below, we will see its syntax to see its implementation see below;

Example:

(usize::max_value(), 0);

e. count_ones(self): This will return us the number of ones int he binary representation. Below, we will see its syntax to see its implementation see below;

Example:

let variable_name = binary_representationusize;
(variable_name.count_ones(), 3);

f. leading_zeros(self): This will return us the number of leading zeros present in the binary representation. Below, we will see its syntax to see its implementation see below;

Example:

let variable_name = binary_representationusize;
(variable_name.leading_zeros(), 3);

g. trailing_zeros(self): This will return us the number of trailing zeros present in the binary representation. Below, we will see its syntax to see its implementation see below;

Example:

let variable_name = binary_representationusize;
(variable_name.trailing_zeros(), 3);

Example of Rust usize

1. In this example, we are trying to create the usize type variable in the rust and trying to print it using the println! method of rust. We have assigned them different values to see the output. This is a sample example for beginners to understand how usize type work and implement it in rust.

Example:

fn main() {
println!("Demo to show usize type in rust !!");
let myvar1 :usize = 100;
let myvar2 :usize = 200;
let myvar3 :usize = 300;
let myvar4 :usize = 400;
let myvar5 :usize = 500;
let myvar6 :usize = 600;
let myvar7 :usize = 700;
println!("Printing result of all the usize type in rust !!");
println!("value inside myvar1 is {}",myvar1);
println!("value inside myvar2 is {}",myvar2);
println!("value inside myvar3 is {}",myvar3);
println!("value inside myvar4 is {}",myvar4);
println!("value inside myvar5 is {}",myvar5);
println!("value inside myvar6 is {}",myvar6);
println!("value inside myvar7 is {}",myvar7);
}

Output:

Rust usize output

Conclusion

As we have understood somewhat how to use it while programming and what is its significance in rust. They are usually a dynamically sized integer type in rust, which always represents a positive value. But their size, or we can say the size of the usize type, majorly depends on the machine architecture; we cannot decide this at compile time.

Recommended Articles

This is a guide to Rust usize. Here we discuss what is its significance in rust and How usize function works in Rust, along with the examples and outputs. You may also have a look at the following articles to learn more –

  1. What is Rust Programming?
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  3. Functional Programming in Java
  4. Careers in R Programming
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