How to assign a string to a character pointer in C?

Question

How do I assign a string to a character pointer in C ?

Suppose I have a string like "1234788654446" and when I assign it to a char pointer, I am getting error like "missing terminating character". What's wrong with the following code ?

The actual problem statement is this : I have a 1000 digit number and i have to find the greatest product of 5 consecutive digits. so when i store the number in a string, I am getting warning: ""Integer constant is too large for its type" and error "Invalid digit 9 in octal constant" .

My code is :

#include<stdio.h>

int main(){

int i=0;

 int a,b,c,d,e,pro,max=0;

char str[] = "73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450";


while(str[i+4] !='\0'){

     a = str[i]-'0';
     b = str[i+1]-'0';
     c = str[i+2]-'0';
     d = str[i+3]-'0';
     e = str[i+4]-'0';;

     pro = a*b*c*d*e;
     if(pro>max)
       max = pro;

i++;
}

 printf("%d",max);

return 0;


}

Answer 1

It looks like the problem is that you're assigning the string over multiple lines. If you're going to do that, make sure you have a \\ followed by no other characters at the end every line during the string assignment so the compiler knows that the string continues below.

Alternative solutions would be to assign the string on one singular line, or wrap each line in quotes.

Example:

char str[] = "73167176531330624919225119674426574742355349194934\
96983520312774506326239578318016984801869478851843\ 
84580156166097919133875499200524063689912560717606\
05886116467109405077541002256983155200055935729725\
71636269561882670428252483600823257530420752963450"; 

Answer 2

Line breaks aren't your friend. You need to do ...

    char str[] = "73167176531330624919225119674426574742355349194934\
96983520312774506326239578318016984801869478851843\
...
71636269561882670428252483600823257530420752963450";

(Notice the \\ on the end of each line, and no leading whitespace on subsequent lines. You can't split a quoted string over multiple lines in C without using \\ )

Option B is:

char str[] = "73167176531330624919225119674426574742355349194934"
             "96983520312774506326239578318016984801869478851843"
             ...
             "71636269561882670428252483600823257530420752963450";

Answer 3

You can't wrap strings like that. You can concatenate them by putting " s around each line:

char str[] = "123"
             "432"
             "543";

Or you can use a backslash \\ to continue lines if you ensure there is no extra whitespace at the beginning.

char str[] = "123\
456\
789";

The warnings are coming because the compiler is interpreting subsequent lines as integers, which are too large to be stored. And a line of digits starting with 0 is interpreted as an octal number, which explains the "invalid digit 9" error.