Q8.c

#include <stdio.h>

int main(void){
    //Number might is too big for even long long int i think, to read in the int, use a string?
    char *num = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
    //13 Adjacent digits, for the greatest product
    //Can't have 0, should have more 9's 8's,
    //Can start from digit one,
    //Produces error "conversion from string literal to 'char' is depracated, BUT STILL WORKS!"
    long long int product = 1, max = 1;
    int i;
    
    for (i=0;i<987;i++){
        //Start from first number, go up 13 times, find product, repeatat with second number
        //can go up to only 987, since there needs to be 13 adjacent digits
        product = ((int)num[i]-48);
        for(int j=i+1;product!=0&&j<i+13;j++){
            product = product * ((int)num[j]-48);
        }
        if(product >= max){
            max  = product;
        }
    }
    
    printf("%lld\n", max);
    
}