how to detect a lowercase or uppercase char?

the tolower(char) toupper(char) functions can be used to convert a char to an upper or lower case. I wanted to use these functions together with a char array, if the character in the array is lower case then convert it to upper case. But i'm not sure how to tell if the character in the array is upper or lower case to run the appropriate function.. any ideas?

ctype.h also contains the functions

Code:

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int isupper(char c);
int islower(char c);

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Testing may be unnecessary.

Code:

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

int main(void)
{
  char text[] = "abc 123 DEF !@#";
  size_t i;
  puts(text);
  for (i = 0; text[i] != '\0'; ++i)
  {
      text[i] = toupper(text[i]);
  }
  puts(text);
  return 0;
}

/* my output
abc 123 DEF !@#
ABC 123 DEF !@#
*/

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Quote:

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Originally Posted by sean_mackrory

ctype.h also contains the functions

Code:

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int isupper(char c);
int islower(char c);

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Actually the parameters are int not char :)

The author of C++ 5 for Dummies wasn't specific.

Yeah but the standard sure is :)