I see Ancient Dragon has typed faster than I and with a more precise version of what to do. As a learning experience here's a sampling of ideas I have about your code:

1) use int main(), not void main()

3) when using statements requiring braces format your code such that you line up the braces so it's easier to make sure you have matching numbers of opening and closing braces. You appear to have 1 too many closing curly brace in the code you posted.

4) if you're going to use scanf(), and for beginners it's okay, though it's not the best way to obtain input, then read in an entire string with use of %s, words instead of %c, &words[i].

All of the above are issues commonly seen in code written by beginners, and more frequently than I like to think, in code I write still.

C Syntax (Toggle Plain Text)

    scanf("%c",&words[i]);}
    atoi(&words[i]);}

scanf("%c",&words[i]);} atoi(&words[i]);}

above is useless. just input the text as normal characters. You don't have to do any conversion at all to get the ascii value of the characters -- data type char already contains the ascii value. To see if its odd or even

C Syntax (Toggle Plain Text)

// get string from keyboard
fgets(words,sizeof(words),stdin);
//
for(int i = 0; words[i]; i++)
{
   if( (words[i] % 2) == 0)
   {
       // even ascii code
   }
}

// get string from keyboard fgets(words,sizeof(words),stdin); // for(int i = 0; words[i]; i++) { if( (words[i] % 2) == 0) { // even ascii code } }

Do you really want me to tell you where to put it??

C Syntax (Toggle Plain Text)

    scanf("%c",&words[i]);}
    atoi(&words[i]);}

scanf("%c",&words[i]);} atoi(&words[i]);}

above is useless. just input the text as normal characters. You don't have to do any conversion at all to get the ascii value of the characters -- data type char already contains the ascii value. To see if its odd or even

C Syntax (Toggle Plain Text)

// get string from keyboard
fgets(words,sizeof(words),stdin);
//
for(int i = 0; words[i]; i++)
{
   if( (words[i] % 2) == 0)
   {
       // even ascii code
   }
}

// get string from keyboard fgets(words,sizeof(words),stdin); // for(int i = 0; words[i]; i++) { if( (words[i] % 2) == 0) { // even ascii code } }