main.go

// main.go
package main

import (
	"bufio"
	"flag"
	"fmt"
	"log"
	"os"
	"strings"
	"time"
)

func main() {
	word:=flag.String("word","","we will try to give you the count it appeared")
	flag.Parse()
	path,err:=os.Getwd()
	file,err:=os.Open(path+"/data.txt")//readfile loads whole thing in memory
	if err!=nil{
		log.Fatal(err)//terminates prgm after showeing err
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	count:=0
	searchword:=strings.ToLower(*word)
	start:=time.Now()
	for scanner.Scan() {
		text := scanner.Text()

		//btext:=[]byte(text)
		// for i:=0;i<len(btext);i++{
		// 	// if(strings.Contains(string(btext[i]),*word)){
		// 	// 	count++
		// 	// }
		// }
		//bufio.scanner gives full line of text , strings is capable of reading full line directly
		text=strings.ToLower(text)
		count+=(strings.Count(text,searchword))
	}
	if err:=scanner.Err();err!=nil{//if error ocurs in scanner.scan it will already exit loop with the limited date it got so after finishing loop we r taking log
		log.Fatal(err)
	}
	fmt.Println(*word,"appeared ",count,"times in data.txt")
	elapsed:=time.Since(start)
	fmt.Println("elapsed time: ",elapsed)
}