Identifier

The program determines if a given identifier is valid or not in a variant of Pascal language, called Silly Pascal. A valid identifier must begin with a letter and must contain only letter or digits. Moreover, it must have at least one character and no more than six characters.

Source in Java

public class Identifier {
  public boolean validateIdentifier(String s) {
    char achar;
    boolean valid_id;
    valid_id = true;
    achar = s.charAt(0);
    valid_id = valid_s(achar);
    if (s.length() > 1) {
      achar = s.charAt(1);
      int i = 1;
      while (i < s.length() - 1) {
         achar = s.charAt(i);
         if (! valid_f(achar))
            valid_id = false;
         i++;
      }
    }
    if (valid_id && (s.length() >= 1) && (s.length() <= 6))
       return true;
    else
       return false;
  }

  public boolean valid_s(char ch) {
    if (((ch >= 'A') &&
         (ch <= 'Z')) ||
        ((ch >= 'a') &&
         (ch <= 'z')))
      return true;
    else
      return false;
  }

  public boolean valid_f(char ch) {
    if (((ch >= 'A') &&
         (ch <= 'Z')) ||
        ((ch >= 'a') &&
         (ch <= 'z')) ||
        ((ch >= '0') &&
         (ch <= '9')))
      return true;
    else
      return false;
  }

  public static void main(String[] args) {
    if (args.length == 0) {
      System.out.println("Usage: identifier.Identifier [string]");
    } 
    else {
      Identifier id = new Identifier();
      if (id.validateIdentifier(args[0])) {
         System.out.println("Valid");
      } 
      else {
         System.out.println("Invalid");
      }
    }
  }
}

Usage:

Command line	Result
java Identifier "abcd12"	Valid
java Identifier "cont*1"	Invalid
java Identifier "2soma"	Invalid
java Identifier "a123456"	Invalid

Source in C

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

int valid_s(char ch)
{
    if (((ch >= 'A') &&
         (ch <= 'Z')) ||
        ((ch >= 'a') &&
         (ch <= 'z')))
      return 1;
    else
      return 0;
}

int valid_f(char ch)
{
    if (((ch >= 'A') &&
         (ch <= 'Z')) ||
        ((ch >= 'a') &&
         (ch <= 'z')) ||
        ((ch >= '0') &&
         (ch <= '9')))
      return 1;
    else
      return 0;
}

int valid_id(char *s)
{
    char achar;
    int valid_id;
    int slen = strlen(s);

    achar = s[0];
    valid_id = valid_s(achar);

    if (slen > 1) {
      achar = s[1];
      int i = 1;
      while (i < slen - 1) {
         achar = s[i];
         if (! valid_f(achar))
            valid_id = 0;
         i++;
      }
    }
    if (valid_id && (slen >= 1) && (slen < 6))
       return 1;
    else
       return 0;
}

int main(int argc, char **argv)
{
    if (argc == 1) {
      printf("Usage: %s [string]\n", argv[0]);
    } else {
      if (valid_id(argv[1])) {
         printf("%s: Valid\n", argv[1]);
      } else {
         printf("%s: Invalid\n", argv[1]);
      }
    }
}

Control flow graph

public boolean validateIdentifier(String s) {
	char achar ;
/* 01 */ boolean valid_id = false;
/* 01 */ if (s.length() > 0) {
/* 02 */ 	achar = s.charAt(0);
/* 02 */	valid_id = valid_s(achar);
/* 02 */ 	if (s.length() > 1) {
/* 03 */		achar = s.charAt(1);
/* 03 */		int i = 1;
/* 04 */ 		while (i < s.length() − 1) {
/* 05 */ 			achar = s.charAt(i);
/* 05 */ 			if (! valid_f(achar))
/* 06 */ 				valid_id = false;
/* 07 */ 			i ++;
			}
		}
	} /* 08 */ 		/* 09 */ 	/* 10 */
	if (valid_id && (s.length() >= 1) && (s.length() < 6))
/* 11 */ 	return true ;
else
/* 12 */ 	return false ;
}

Definition graph

Definition-use graph