Add vector examples

collections/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "collections"
+version = "0.1.0"
+authors = ["laurens <miers132@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

collections/src/main.rs

@@ -0,0 +1,78 @@
+fn vector_tests() {
+    let mut v: Vec<i32> = Vec::new();
+    let mut c = vec![1, 2, 3];
+
+    println!("Elements in vector:");
+    for el in v.iter() {
+        println!("{}", el);
+    }
+
+    println!("Elements in vector:");
+    for el in c.iter() {
+        println!("{}", el);
+    }
+
+    v.push(1);
+    v.push(2);
+    v.push(3);
+    v.push(4);
+
+    c.push(4);
+
+    println!("Elements in vector after update:");
+    for el in &v {
+        println!("{}", el);
+    }
+
+    println!("Elements in vector after update:");
+    for el in c.iter() {
+        // Just another way for iterating over a vector
+        println!("{}", el);
+    }
+
+    let t: &i32 = &v[2];
+    println!("The third element is {}", t);
+
+    match v.get(2) {
+        Some(third) => println!("The third element is {}", third),
+        None => println!("ERROR: no third element"),
+    }
+
+    // Following code panics because we go out-of-bounds
+    // let _does_not_exist = &v[100];
+
+    // Folling code does not panic but returns None
+    let does_not_exist = v.get(100);
+
+    match does_not_exist {
+        Some(temp) => println!("ERROR: None should have been returned {}", temp),
+        None => println!("Out-of-bounds: get returns None"),
+    }
+
+    // vector that holds multiple types using enums
+    enum SpreadsheetCell {
+        Int(i32),
+        Float(f64),
+        Text(String),
+    }
+
+    let row = vec![
+        SpreadsheetCell::Int(3),
+        SpreadsheetCell::Text(String::from("blue")),
+        SpreadsheetCell::Float(10.12),
+    ];
+
+    println!("----------");
+    println!("Vec with different types:");
+    for v in &row {
+        match v {
+            SpreadsheetCell::Int(i) => println!("Integer: {}", i),
+            SpreadsheetCell::Float(f) => println!("Float: {}", f),
+            SpreadsheetCell::Text(s) => println!("String: {}", s),
+        }
+    }
+}
+
+fn main() {
+    vector_tests();
+}