Thread: limit the characters using gets function

Hello

Any one know how to limit the character input
by user if I use gets()?

My program works, it suppose to compare two
line enter by user and see if they are the same, but I think I need a loop some where
to tell the user they enter to many characters
if they enter more then 25 characters. The following is my code, can someone please take it look and give me some suggestions, thank you.

#include <stdio.h>
#include <stdlib.h>

int compare(char *, char *); /* Function prototype for compare two lines */

int main(void)

{
char array_1[26];
char array_2[26];

/* Have user enter two line */
printf("\nPlease enter two lines, with maximum of 25 characters per line\n") ;

gets(array_1); /* store the first line enter by user to array_1 */
gets(array_2); /* store the second line enter by user to array_2 */

/* Call function to compare the two array, and output the the results
of lines are equal or not equal to screen */

if(compare(array_1, array_2))
printf("\nThe two line are equal\n");
else
printf("\nThe two line are not equal\n");

return;
}

/* Function definition of compareing two line (arrays) */
int compare(char *array_1, char *array_2)

{
int value;

/* Use while loop to compare one character at a time from two arrays */
while (*array_1 == *array_2 && *array_1 != '\0')

{
++array_1;
++array_2;
}

if(*array_1 == *array_2)
value = TRUE;
else
value = FALSE;

return (value); /* return the value to the main */
}

Any one know how to limit the character input
by user if I use gets()?

Can't be done. But you can use fgets to do this. Specify the input stream as standard input (stdin).

Also you can't compare arrays with logical operators. You must use 'strcmp' and test it's return value.

Troll_King,

Thanks for your input, the reason that I didn't use strcmp because teacher don't want us to use
it, she want us to write the "strcmp" function ourself. fgets?? I though we only can use fgets with a open read file, we never learn how to use fgets with stdin, can you give me a example please? thank you

yukon

Thanks Troll_King,

By the way, what did you do to witch King???

Code:

#include "stdafx.h"
#include<stdlib.h>

#define TRUE 0
#define FALSE 1
int CompareStrings(char [],char []);
void GetString(char []);

int main()
{
	char array_1[30];
	char array_2[30];
	int status;

	GetString(array_1);
	GetString(array_2);

	status = CompareStrings(array_1,array_2);

	if(status == TRUE)
	{
		printf("\nThe strings are equivalent.");
	}
	else
	{
		printf("\nThe strings are different.");
	}

  return 0;
}

void GetString(char ar[])
{
	printf("Enter string: ");
	fgets(ar,29, stdin);
}

// Function definition of compareing two (arrays)  
int CompareStrings(char array_1[], char array_2[]) 
{ 
	int index;
	int value = TRUE; 

	// loop and compare one character at a time from two arrays  
	for(index = 0; array_1[index] != '\0'; index++) 
	{ 

		if(array_1[index] == array_2[index])
		{
			continue;
		}
		else
		{
			return value = FALSE;
		}
	} 

	return value; 
}

Umm, the Witch King was slain. He might some back as an undead specter though.

Troll King,

I lost the connection to C borad last night,
I'm at work right now, but, I'll study the example you give me and try to change my code tonight.

Thanks again for all your help !!!

Yukon