Euler problem no 8

[clmlbx]

To solve:-

Problem 8 - Project Euler

Find the greatest product of five consecutive digits in the 1000-digit number.

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450​

solution:-

#include <stdio.h>
#include <stdlib.h>


int main()
{
    int i,j,larg =0,prod;

    char series[1000] = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";

    for(i=0;i<=996;i++){
            prod = 1;
     for(j=i;j<=i+4;j++){
        prod = prod * series[j];
        printf("\n j = %d prod = %d number = %d",j,prod,series[j]); // just used for debugging
        }
        if(prod > larg){
            larg = prod;


        }


    }
    printf("\n\n%d large",larg);
    return 0;
}

problem:-

I believe logic is correct only problem I found while debugging is .. I am getting garbage value in series[j].. reason I could understand is as it is character and I am performing maths action.. so I did try type casting like this "(int) series[j]" but still no luck.. ..

so guys help me out in this.. and also I need explanation on how it should be done.

Forgot to mention but many would have understood.

language: c

Using codeblocks

 

[harshilsharma63]

Store the sequence of numbers in an integer array (what made you think of storing it in a String?).

 

[clmlbx]

Please explain how will I store that 1000 digit number in int array.. I believe I will have to manually add each to it's index.. is that right way to do .. ?

 

[harshilsharma63]

Please explain how will I store that 1000 digit number in int array.. I believe I will have to manually add each to it's index.. is that right way to do .. ?

That's a noob's way to do. A programmer's way to do it would be to store the sequence in a text fir (without any spaces), create an integer array of size 1000, then read the text file and insert the numbers one by one programmatically. You may also generate the numbers randomly rather than reading them from a file

 

[clmlbx]

hmm.. ok then.. FYI I am still learning c.. have not yet came to file handling..recently finished array... and yes I can generate random numbers but .. question is to find from that 1000 digit number

but there should be a way doing by type casting.. converting that character to int..

 

[harshilsharma63]

hmm.. ok then.. FYI I am still learning c.. have not yet came to file handling..recently finished array... and yes I can generate random numbers but .. question is to find from that 1000 digit number

but there should be a way doing by type casting.. converting that character to int..

You can generate 1000 randon single digit numbers to initialize the array. BTW you may also learn file handling from the Web; it's nothing difficult, just a few line of code of accessing a file

 

[Nerevarine]

temp=series[j];
prod = prod * temp;


try this ?
temp being integer

 

[clmlbx]

^^ already did.. not working

 

[harshilsharma63]

^^ already did.. not working

Have you been able to initialize the integer array?

 

[clmlbx]

it is giving error as I guess character can not be stored in int..

 

[harshilsharma63]

it is giving error as I guess character can not be stored in int..

You can use the function "stoi()" if it's available. Or a simple switch-case would also work as you'll be reading only a single character at a time, so there will only be 10 cases.

 

[nightcrawler]

Assuming it a 1 byte char (not unicode etc) Replace prod = prod * series[j]; with prod = prod * (series[j] - 48);

 

[clmlbx]

^^ yes, that solved the problem

Answer to that question is

Spoiler

40824

Thanks