Simple function that I tried to build.

**Scripter** · 10-23-2002

Hi, I just started to learn C 5 hours ago.
I tried to build a simple function that simulates the substr() function of JavaScript, php, etc.

now lets look at the problem:
let me say, my string is: I S A A C.
and I make sub(mystr, 0, 2).
Ok, the program write's me: ISA (Until here its all ok..) and a lot of @#$%^& (This is the problem).

Now, I know that is because the others characters didnt received any value, but I havent any idea how to solve the problem.

The code:

Code:

#include <stdio.h>
#include <conio.h>

int strll(char str[10]);
void sub(char string[10], int min, int max);

int main()
{
	char str[10];
	printf("String: ");
	gets(str);
	printf("\n");
	sub(str,0,2);
	
	return 0;
}

int strll(char str[10])
{
	int i;

	for(i = 0; str[i] != '\0'; i++);
	return i;
}

void sub(char string[10], int min, int max)
{
	char strcp[10];
	int i, j;
	j = 0;

	for(i = min; i <= max; i++)
	{
		strcp[j] = string[i];
		j++;
	}
		
	printf("%s",strcp);
}

or : http://scripter.fresh.li/substr.txt

Thanks,
Isaac.

**Sargnagel** · 10-23-2002

Hmmm ... I don't get any strange output.
But the output for string 'I S A A C' is not 'ISA' ... it's just 'I S' but that's obvious.

And what about your function 'strll' ... you don't use it?!

Code:

deleted

**Scripter** · 10-23-2002

I want a function Like substr() (Substring)..
Thanks for trying to help.

**Sargnagel** · 10-23-2002

@String echo:
oops .. sorry. You're right! Just a few minutes ...

What compiler/OS are you using?

**Scripter** · 10-23-2002

Code:

#include <stdio.h>
#include <conio.h>

int strll(char str[10]);
void sub(char string[10], int min, int max);

int main()
{
	char str[10];
	printf("String: ");
	gets(str);
	printf("\n");
	sub(str,0,2);
	
	return 0;
}

int strll(char str[10])
{
	int i;

	for(i = 0; str[i] != '\0'; i++);
	return i;
}

void sub(char string[10], int min, int max)
{
	char strcp[10];
	int i, j,k;
	j = 0;

	for(i = min; i <= max; i++)
	{
		strcp[j] = string[i];
		j++;
	}
	

   for(i = 0; i <= max; i++)
	   printf("%c",strcp[i]);

   printf("\n");
	
	
}

Not bad to a 5 hour's programmer(newbie) in C, right?

**Sargnagel** · 10-23-2002

Damn, you were faster.

Really not bad for a 5 h newbie!
But anyway here is my interpretation of the substring() function of JAVA. It's very basic and not secure!

Code:

#include <stdio.h>

int strll(char str[]);
void sub(char string[], int min, int max);

int main()
{
	char str[10];
	int start, end;
	printf("String: ");
	gets(str);
	printf("\nstart: ");
	scanf("%d", &start);
	printf("\nend: ");
	scanf("%d", &end);
	
	sub(str,start-1,end-1);
	
	return 0;
}

void sub(char string[], int min, int max)
{
	int i;
	
	for(i = min; i <= max; i++)
	{
		printf("%c", string[i]);
	}	
}

**Scripter** · 10-23-2002

Thanks.

**Hammer** · 10-23-2002

@Scripter

A couple of pointers for you:

Names begining str followed by a letter are reserved for implementation use, so steer clear of them.

gets() is a bad function to use, lookup fgets() and learn how to use that. gets() is a very typical starting point for a newbie, but get over it as soon as you can.

char str[10]; <-- is way too small for an input buffer from the user, and the good old gets() function will exploit that weakness.

Have fun

**Scripter** · 10-23-2002

I will try soon as I can to start using fgets() instead gets().
Can you give me an example, how to use fgets()?

On this example:

Code:

#include <stdio.h>

int main()
{
	char name[100];
	printf("Please insert your name: ");
	gets(name);
	printf("\nYour name is %s, right?\n",name);

	return 0;
}

How could, I use in this example, fgets() instead gets()?
Thanks!

**dbaryl** · 10-24-2002

Here's somewhere you might refer to:

http://www.rt.com/man/fgets.3.html

**Scripter** · 10-24-2002

Thanks a lot.

Thread: Simple function that I tried to build.

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Simple function that I tried to build.

What you gave me is just to echo a string

I fixed the problem :)

Thanks Again for the Help!

Ok, I got it.

dbaryl and Salem, Thanks.

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