Question

Write a C function that returns nothing, but does something like this:

Enter a number:
>>> 23879
the number 23879 has 5 digits.

Enter a number:
>>> 3.14159265359
The number 3.14159265359 has 12 digits

Answer 1

challenging huh.

Answer 2

alright just do the first part, which only accepts integers

Answer 3

i dont know how to write the code exactly, but you can do that by, take the log base 10 of that number, round down, then add one to count the digit.

Answer 4

log base 10? O.o what about the modulo operator

Answer 5

Hmm let c be the number

c%10 = b
c - b = c/10
c%10 = b
c- b = c/10 hmm run this process in a loop and we will check if c <= 10 at the end of the loop
i + 1 must be the count

Answer 6

the log base 10 trick works!

Answer 7

but it only works for non-negative numbers... how do I fix that?

Answer 8

make the number positive if it's negative

Answer 9

hah alright those all work

Answer 10

now how do I count real numbers like 3.14159265359

Answer 11

is there some function which separates out the int and frac part?

Answer 12

you can always make one in C :-D

Answer 13

Oh Cool, so how do you do that?

Answer 14

void ndigits(void) {
enum {NUMLENGTH = 100};
char number[NUMLENGTH];
char c;
int i, digits;
digits = i = 0;
printf("Enter a number: ");
while ((c = getchar()) != '\n') {
number[i++] = c;
if (c != '-' && c != '.') ++digits;
}
number[i] = '\0';
printf("The number %s has %d digits", number, digits);
}

Answer 15

too bad if i enter something like 'HELLO' it thinks that's a 5 digit number.

Answer 16

void ndigits(void) {
typedef enum {false, true} bool;
enum {NUMLENGTH = 100};
char number[NUMLENGTH];
char c;
bool is_a_number;
int i, digits;
digits = i = 0;
is_a_number = true;
printf("Enter a real number (base 10): ");
while ((c = getchar()) != '\n') {
number[i++] = c;
if (c != '-' && c != '.' && is_a_number) {
(c - '0' < 0 || c - '0' > 9) ? is_a_number = false : ++digits;
}
}
number[i] = '\0';
if (! is_a_number) {
printf("%s is not a number.\n", number);
} else {
printf("The number %s has %d digits", number, digits);
}
}

Answer 17

how do I suppress the "comparison between unsigned and signed" warning?

Answer 18

There now it's refactored:
int ndigits(void) {
typedef enum {false, true} bool;
enum {NUMLENGTH = 100};
char* number = malloc(sizeof(number) * NUMLENGTH);
unsigned char c;
bool is_a_number;
int i, digits;
digits = i = 0;
is_a_number = true;
printf("Enter a real number (base 10): ");
while ((c = getchar()) != '\n') {
number[i++] = c;
if (c != '-' && c != '.' && is_a_number) {
if (c - '0' < 0 || c - '0' > 9) {
is_a_number = false;
} else {
++digits;
}
}
}
number[i] = '\0';
if (! is_a_number) {
printf("%s is not a base 10 number.\n", number);
} else {
printf("The number %s has %d digits", number, digits);
}
free(number);
return is_a_number;
}

Answer 19

How do I refactor it further?

Answer 20

Also, can anyone implement it in Python?

Answer 21

go to computer science section?

Answer 22

Nobody's there :-P but I'll try