Detect vowels in a string

Question

Im trying to write a function that detects vowels and digits in a string. iterating through the string, im trying to do a one-line if statement to check if a character is a vowel. Code as below...

void checkString(char *str)
{
    char myVowels[] = "AEIOUaeiou";

    while(*str != '\0')
    {
        if(isdigit(*str))
            printf("Digit here");
        if(strchr(myVowels,*str))
            printf("vowel here");
        str++;
    }
}

The digit checking works perfectly. However "(strchr(myVowels,*str))" doesnt work. It says different types for formal and actual parameter 1. Can anyone help me here? Thanks

try typecasting str* to a char before passing it to the function — Techmonk, Feb 11 '13 at 10:48
@Techmonk You don't need to cast anything since `*str` is already a `char`. It should work as is. — cnicutar, Feb 11 '13 at 10:48
Just two notes: (1) BTW, English does not consider 'y' to be vowel too? (I'm Czech, so not sure here. But in Czech it is vowel too.) (2) Note that some languages have more vowels (e.g. ě, á, í, é etc.) — mity, Feb 11 '13 at 10:52
@mity `y` is "fuzzy". It's a vowel in words like `type` and `pity` but not in words like `boy` and `yell`. — Alexey Frunze, Feb 11 '13 at 10:57

score 1 · Accepted Answer · answered Feb 11 '13 at 10:54

1

Most likely you haven't included proper header files.

This works just fine:

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

void checkString(const char *str)
{
    char myVowels[] = "AEIOUaeiou";

    printf("checking %s... ", str);

    while(*str != '\0')
    {
        if(isdigit(*str))
            printf("Digit here ");
        if(strchr(myVowels,*str))
            printf("vowel here ");
        str++;
    }

    printf("\n");
}

int main(void)
{
  checkString("");
  checkString("bcd");
  checkString("123");
  checkString("by");
  checkString("aye");
  checkString("H2CO3");
  return 0;
}

Output (ideone):

checking ... 
checking bcd... 
checking 123... Digit here Digit here Digit here 
checking by... 
checking aye... vowel here vowel here 
checking H2CO3... Digit here vowel here Digit here

answered Feb 11 '13 at 10:54

Alexey Frunze

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Note that it's often necessary to convert the argument to the ``'s `is...()` functions to `unsigned char`. See [the manual page](http://www.manpagez.com/man/3/ctype/). – unwind Feb 11 '13 at 10:59
@unwind Interesting detail, thanks. I'd assume we're dealing with ASCII chars (as EBCDIC and others are virtually extinct) and so all is well. – Alexey Frunze Feb 11 '13 at 11:05
Guess it was something to do with missing headers. Thanks works perfectly now – kype Feb 11 '13 at 11:23
@user1234897 To prevent such bugs in the future, get a modern C compiler with support for a newer version of the C standard (C99 or later). If you had forgotten to include that header on a C standard compiler, you would have gotten a compiler error. – Lundin Feb 11 '13 at 12:15

Detect vowels in a string

1 Answers1