how to check for chars?

This is a discussion on how to check for chars? within the C Programming forums, part of the General Programming Boards category; Okay, I have to somehow check an integer value for a character or punctuation character. The catch is that the ...

  1. #1
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    Post how to check for chars?

    Okay, I have to somehow check an integer value for a character or punctuation character. The catch is that the variable has already been read in; therefor I cannot use getch() or.. can I???

    Okay, as you can see below, I read in a value and store it as a float, after I store it as a float, I check and see if it is actually a float (double) value. If it is .0, then I know it is an integer so I convert the float to an integer and return 0 to main() to let it know that the user has entered a valid integer.

    currently I have the following which checks for float values and it works as long as a period is not entered or a character is not entered. Any ideas ? Suggestions? Again, the value is set and I cannot use getch unless I can take it from a pre-assigned variable.

    Code:
    int input_validate()  {
    int guess;
    
    double temp=12,temp2,i_part;
    
     temp2=temp;
      
     if (modf(temp,&i_part)>0.)     /*  Checks for a double value  */
       return -1;
     else  {
       guess=(int)temp2;   /*Stores the temp value into guess as Integer */
       if ((guess<100)&&(guess>=0)) 
         return 1;
       else
         return -1;
     }
    }
    Any ideas how i can check for chars and punctuation??? Thanks.

  2. #2
    Just one more wrong move. -KEN-'s Avatar
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    Try reading value into a string, then parsing it and converting it using atof() or atoi().

  3. #3
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    RE: KEN

    Okay, would this work correctly?

    inside of a function of course:

    Code:
    int var1;
    char strg[10];
    
    
    strg=var1;
    now my question is, how would I parse each individual character from that string? I understand a for loop and or a while loop, but how would I break it apart in the first place?

  4. #4
    End Of Line Hammer's Avatar
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    >>how would I parse each individual character from that string?
    This prints each character one at a time. You can change it to do whatever you want.

    Code:
    for (i = 0: i < Length; i++)
    {
      putchar(mystring[i]);
    }
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

  5. #5
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    Well it seems that you could benefit from the ctype library. There you will find such functions as isalpha(), isspace() and so forth.

  6. #6
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    string problem

    how do i get a double variable stored into a string? I cannot just let the string get thh double.

    here's what i have: assume var's initialized and declared:

    Code:
    double temp=90;
    char temp_str[5]
    temp_str=temp;
    
    /* OTHER CODE HERE */
    
    for(i=0; i<N; i++)  {
            if(isdigit(temp_str[i])!=0)
             return 0;
            else 
             return -1;
          }
    Last edited by justin69enoch; 01-28-2003 at 10:25 PM.

  7. #7
    End Of Line Hammer's Avatar
    Join Date
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    >>how do i get a double variable stored into a string?
    Lookup sprintf()
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

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