Thread: how to fix this pattern code..

i fixed it to
if (*input==')'){
and it ran and said that its valid
but when I changed the input to "(1,2) (34,5) (6 7,8)"

It also says that its valid.
??

whats incomplete?

Code:

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

int is_valid(const char *input);
const char *match_pair(const char *input);

int main()
{
    char input[] = "(1,2) (34,5) (6  7,8)";
    if (is_valid(input))
    {
        printf("%s is valid.\n", input);
    }
    else
    {
        printf("%s is invalid.\n", input);
    }

    return 0;
}

/* Match one or more consecutive digits and return a pointer to the first char
 * that is not a digit.
 */
const char *match_number(const char *input)
{
    while((*input<='9')&&(*input>='0')){

     input++; //increasing the  address by1
    }

    return input;
}

/* Match "(<number>,<number>)" pattern.
 * Return a pointer to the first char after the matched pattern, or
 * NULL if there is no match.
 */
const char *match_pair(const char *input)
{
       if (*input != '(')
      {
        return NULL;
      }

    input = match_number(input + 1); //it wiil get char '2'

   if (*input == ',') {   //'2' differs ','

         input = match_number(input + 1);
        if (*input==')'){
         return input;
        }
        else
          return NULL;
    }
    else
      return NULL;
   }
/* Match "(<number>,<number>) (<number>,<number>) (<number>,<number>)" pattern.
 * Return 1 if there is a match and 0 otherwise.
 */
int is_valid(const char *input)
{
    input = match_pair(input);
    if (input == NULL)
    {
        return 0;
    }

    else{

    return 1;
    }

}

In the is_valid function i created a loop which runs forward to the next pair each time.
but it gives me the same valid result for
"(1,2) (34,5) (6 7,8)"

??

Code:

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

int is_valid(const char *input);
const char *match_pair(const char *input);

int main()
{
    char input[] = "(1,2) (34,5) (6  7,8)";
    if (is_valid(input))
    {
        printf("%s is valid.\n", input);
    }
    else
    {
        printf("%s is invalid.\n", input);
    }

    return 0;
}

/* Match one or more consecutive digits and return a pointer to the first char
 * that is not a digit.
 */
const char *match_number(const char *input)
{
    while((*input<='9')&&(*input>='0')){

     input++; //increasing the  address by1
    }

    return input;
}

/* Match "(<number>,<number>)" pattern.
 * Return a pointer to the first char after the matched pattern, or
 * NULL if there is no match.
 */
const char *match_pair(const char *input)
{
       if (*input != '(')
      {
        return NULL;
      }

    input = match_number(input + 1); //it wiil get char '2'

   if (*input == ',') {   //'2' differs ','

         input = match_number(input + 1);
        if (*input==')'){
         return input;
        }
        else
          return NULL;
    }
    else
      return NULL;
   }
/* Match "(<number>,<number>) (<number>,<number>) (<number>,<number>)" pattern.
 * Return 1 if there is a match and 0 otherwise.
 */
int is_valid(const char *input)
{

    for(input = match_pair(input);input!=NULL;input = match_pair(input))
    {
      if (input == NULL)
        {
          return 0;
        }

         
    }
    return 1;
}

i wrote this iterative function
but on the for line it says
|66|error: invalid operands to binary +|
|66|warning: assignment discards qualifiers from pointer target type|

what is the problem in the for line?

Code:

int is_valid(const char *input)
{
char *temp;
    for(temp=input;temp!=NULL;temp =temp+ match_pair(input)) //line 66
    {
      if (temp == NULL)
        {
          return 0;
        }


    }
    return 1;
}

You can't assign a const char * (like, say, input) to a just-plain char * (like, say, temp). You lose the const that way.

how to iterate from one end ')' to the next one??

i tried to check the next ')' each time
but its not working.

Code:

int is_valid(const char *input)
{
    while (*input!=')'){
      input = match_pair(input);
      input++;
    }
      if (input == NULL)
      {
        return 0;
      }

      else{

      return 1;
      }

}

One last hint before I give up on this thread:

Code:

for(input = match_pair(input);*input != '\0';input = match_pair(input))
	{
                   if (input == NULL)
                       {
                                return 0;
                       }
	}
      if (*input!=')')
            {
        return 1;
             }   
}

I changed '\0' to ')'
It didnt solved it.
I get an endless loop.
and then it says that it encountered an error and needed to close.

Code:

for(input = match_pair(input);*input != ')';input = match_pair(input))
	{
                   if (input == NULL)
                       {
                                return 0;
                       }
	}
      if (*input!=')')
            {
        return 1;
             }

and i did the last other option
its not working
??

Code:

int is_valid(const char *input)
{
    input = match_pair(input);
    if (input == NULL)
    {
        return 0;
    }

    /* Fill in your code here */

	for(input = match_pair(input);*input != '\0';input = match_pair(input))
	{
                   if (input == NULL)
                       {
                                return 0;
                       }
	}
      if (*input!='\0')
            {
        return 1;
             }   
}

for "(1,2) (34,5) (6 7,8)" it says that its invalid which is correct
but when i put
"(1,2) (34,5) (67,8)" it says that its invalid which is wrong

??