prob8.go

package main

import (
    "fmt"
    "strconv"
)

const (
    thenumber string = 
    "73167176531330624919225119674426574742355349194934"+
    "96983520312774506326239578318016984801869478851843"+
    "85861560789112949495459501737958331952853208805511"+
    "12540698747158523863050715693290963295227443043557"+
    "66896648950445244523161731856403098711121722383113"+
    "62229893423380308135336276614282806444486645238749"+
    "30358907296290491560440772390713810515859307960866"+
    "70172427121883998797908792274921901699720888093776"+
    "65727333001053367881220235421809751254540594752243"+
    "52584907711670556013604839586446706324415722155397"+
    "53697817977846174064955149290862569321978468622482"+
    "83972241375657056057490261407972968652414535100474"+
    "82166370484403199890008895243450658541227588666881"+
    "16427171479924442928230863465674813919123162824586"+
    "17866458359124566529476545682848912883142607690042"+
    "24219022671055626321111109370544217506941658960408"+
    "07198403850962455444362981230987879927244284909188"+
    "84580156166097919133875499200524063689912560717606"+
    "05886116467109405077541002256983155200055935729725"+
    "71636269561882670428252483600823257530420752963450"
)

func Multiply(nums string) (value int){
    total := 1

    for i:=0; i < len(nums); i++ {
        value,err := strconv.Atoi(nums[i:i+1])
        if err != nil {
            panic(0)
        }
        total *= value
    }

    return total
}

func main() {
    biggest := 0

    for end := 5; end < len(thenumber); end++ {
        nums := thenumber[end-5 : end]
        current := Multiply(nums)

        if current > biggest {
            biggest = current
        }
    }

    fmt.Printf("The biggest product is %d\n", biggest)
}