Thread: converting a string to an array

Hey

I need to write a program that stores a number as an array. Im pretty new to programming, been looking around for a couple hours now and have had no luck. Sorry if this has been asked before.

this is an example of what I want...

user inputs 14364 as a string (scanf("%s",number))

The number then gets stored in an array like this

int number[5];

number[0]=1
number[1]=4
number[2]=3
number[3]=6
number[4]=4

Any help would be greatly appreciated!

Dave

First, if you do a scanf with a "%s", you need to put it in a char array, say char input[16]. Since a character is stored as number, you can then happily assign each element in the char array to an element in the integer array. Psuedo code:

Code:

read input
for i = 0..index of last character inputted
    number[i] = input[i]

Thanks for the help. It mostly makes sense.

So right now it will look something like this...

Code:

#include<stdio.h>
#include<string.h>

int main(void)
{

char input[5];
printf("enter a 5 digit number\n")\
scanf("%s",input)


char number[5]; 

/*use for loop to convert each value of the string to a value in the array*/

for(i = 0; ***;***)
{    
number[0] = input[0];
}

return 0;
}

the ***'s are where i am not sure what to do

Dave

Do you have any ideas about how to use a for loop or any programming experience? Just giving you the code wouldn't do much good if you can't even figure out the 3rd pard of the for loop (or the guts of it, which I basically gave you). Perhaps read up here first: Cprogramming.com Tutorial: Loops.

Originally Posted by anduril462

First, if you do a scanf with a "%s", you need to put it in a char array, say char input[16]. Since a character is stored as number, you can then happily assign each element in the char array to an element in the integer array. Psuedo code:

Code:

read input
for i = 0..index of last character inputted
    number[i] = input[i]

It's not that simple.... The string will conatin ASCII values. The ASCII character "1" is actually valued at 49.

If you simply put the 14364 characters in the example into your integer arry you're going to end up with... 49, 52, 51, 54, 52 and I'm guessing that's not quite what you are looking for...

There is a conversion that has to take place between ASCII and binary representations... Basically you have to subtract 48 from each character and test each time that the result is between 0 and 9 to filter out possible letters or punctuation marks.

Doh! Thanks Tater, don't know how I missed that one.

Originally Posted by anduril462

Doh! Thanks Tater, don't know how I missed that one.

Well, it's kind of non-obvious unless you've been there and tripped over it once or twice....

Originally Posted by CommonTater

Well, it's kind of non-obvious unless you've been there and tripped over it once or twice....

I have, several times. I've been at this for 10 years or so...that's the sad part.

Originally Posted by laserlight

I would rather check that the character is in the range ['0', '9'] and then subtract '0'.

Yep... that'll work too.

Originally Posted by anduril462

I have, several times. I've been at this for 10 years or so...that's the sad part.

Don't feel bad... I've been at this a while too and I still trip over stuff all the time.

Originally Posted by anduril462

Do you have any ideas about how to use a for loop or any programming experience? Just giving you the code wouldn't do much good if you can't even figure out the 3rd pard of the for loop (or the guts of it, which I basically gave you). Perhaps read up here first: Cprogramming.com Tutorial: Loops.

yep, I have done a lot of while loops and do while loops. Never really had a reason to use a for though. I know how a for loop works... (starting number;condition;what happens to number when loop executes) i am just not sure what you mean by index of last character input.

Originally Posted by CommonTater

It's not that simple.... The string will conatin ASCII values. The ASCII character "1" is actually valued at 49.

If you simply put the 14364 characters in the example into your integer arry you're going to end up with... 49, 52, 51, 54, 52 and I'm guessing that's not quite what you are looking for...

There is a conversion that has to take place between ASCII and binary representations... Basically you have to subtract 48 from each character and test each time that the result is between 0 and 9 to filter out possible letters or punctuation marks.

Before I posted here I read a bunch of tutorials (and looked up string.h library) and I had it working perfectly fine. Only problem is I was getting numbers like 49,52 etc... and it didnt make any sense to me! This actually helps alot! Thanks