Add option to calculate program duration

README.md

@@ -26,7 +26,7 @@ brew install tasnimAlam/word-counter/word_counter
 ## Usage
 
 ```console
-$ ./word_counter poem.txt --top 4 --search lover
+$ ./word_counter poem.txt --top 4 --search lover --max --duration
 +---------------+-------+---+
 | Search result | lover | 3 |
 +---------------+-------+---+
@@ -44,6 +44,7 @@ $ ./word_counter poem.txt --top 4 --search lover
 +-------+-------+
 | lover | 3     |
 +-------+-------+
+Duration : 2ms 
 ```
 
 ## Options
@@ -56,10 +57,11 @@ USAGE:
     word_counter [FLAGS] [OPTIONS] <input>
 
 FLAGS:
-    -h, --help       Prints help information
-    -r, --reverse    Reverse order
-    -m, --max        Show most counted word
-    -V, --version    Prints version information
+    -d, --duration    Duration of all the calculations
+    -h, --help        Prints help information
+    -r, --reverse     Reverse order
+    -m, --max         Show most counted word
+    -V, --version     Prints version information
 
 OPTIONS:
     -o, --output <output>    Output file

src/lib.rs

@@ -7,6 +7,7 @@ use std::error::Error;
 use std::fs::File;
 use std::io::prelude::*;
 use std::path::PathBuf;
+use std::time::Instant;
 use structopt::StructOpt;
 #[macro_use]
 extern crate prettytable;
@@ -38,12 +39,17 @@ pub struct Opt {
     #[structopt(short = "m", long = "--max")]
     show_max: bool,
 
+    /// Duration of all the calculations
+    #[structopt(short = "d", long = "--duration")]
+    duration: bool,
+
     /// Output file
     #[structopt(short, long, parse(from_os_str))]
     output: Option<PathBuf>,
 }
 
 pub fn run(opt: Opt) -> Result<(), Box<dyn Error>> {
+    let time = Instant::now();
     // Read contents from file
     let mut f = File::open(opt.input)?;
     let mut contents = String::new();
@@ -90,6 +96,11 @@ pub fn run(opt: Opt) -> Result<(), Box<dyn Error>> {
     // Print count table
     print_counts(&result);
 
+    // Print program duration
+    if opt.duration {
+        println!("Duration : {}ms", time.elapsed().as_millis());
+    }
+
     Ok(())
 }