Dealing with ints that are in char array

This is a discussion on Dealing with ints that are in char array within the C Programming forums, part of the General Programming Boards category; I have a char array that has both ints and letters in it. I'm trying to take two numbers from ...

  1. #1
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    Dealing with ints that are in char array

    I have a char array that has both ints and letters in it.

    I'm trying to take two numbers from this array and add them together, but I presume, seeing as they are stored as characters, that I'm doing something silly like adding there ascii values together.

    How do I treat them as inegers? I tried calling the array using int string1[], but that didn't help.

    Obviously this is wrong...

    Code:
    int x;
    x = string2[1] + string3[1];

  2. #2
    Code Goddess Prelude's Avatar
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    >I'm doing something silly like adding there ascii values together.
    That's it exactly.

    >How do I treat them as inegers?
    You need to convert the strings to integers using a standard function like strtol or a handwritten routine that does the same thing.
    My best code is written with the delete key.

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    I'm trying to use the function atoi for the time being, and amhaving problems:

    Code:
    int x = atoi(string2[1]);
    101 C:\Documents and Settings\Chrisss\My Documents\C\assembler.c [Warning] passing arg 1 of `atoi' makes pointer from integer without a cast

    Can anybody see the problem here?

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    It would be easier to find the exact answer if we knew what type was string2 but my first guess is that string2 is a char*; thus, accessing its second parameter returns a char where-as atoi() is taking a char*.

  5. #5
    Code Goddess Prelude's Avatar
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    >I'm trying to use the function atoi for the time being
    Don't use atoi, it's very easy to bumble into the subtle problems without knowing it and invoke undefined behavior. strtol is much better.

    >Can anybody see the problem here?
    string2[i] is a character, not a character string. If you must use a slice (which are tricky even on a good day), do this:
    Code:
    int x = atoi ( &string2[i] );
    My best code is written with the delete key.

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