Character Replacement in a string

[junglist]

Hi,
i would like your help in a program.

#include <stdio.h>
#include <string.h>
char s[1000];
int i,j,r,k,l;

int counter_aA (m)

{
k=0;
   for(i=0; i<m; i++)
    {
      if (s[i]=='a'||s[i]=='A')
        k++;

    }
 return k;
    }

int counter_zZ (m)
{
 l=0;

   for(i=0; i<m; i++)
    {
      if (s[i]=='z'||s[i]=='Z')
        l++;
    }

        return l;

}



 int main()
{
  printf("Enter Text Line and press ENTER :");
  gets(s);
  r=strlen(s);

  printf("\n\n\n\nThe text is: ");
  puts(s);
  printf("\nThe number of aA is : %d\n",counter_aA(r));
  printf("The number of zZ is : %d\n",counter_zZ(r));


  if (k>l)
  {
      for(i=0; i<strlen(s); i++)
    {

     if (s[i]=='a')
      s[i]='z';
      if (s[i]=='A')
      s[i]='Z';
    }
printf("\n\n\n\nThe modified text is: ");
puts(s);
printf("\nThe NEW number of aA is : %d\n",counter_aA(r));
printf("The NEW number of zZ is : %d\n",counter_zZ(r));

}
else
      if (k<l)
{

    for(i=0; i<strlen(s); i++)
 {
      if (s[i]=='z')
      s[i]='a';
      if (s[i]=='Z')
      s[i]='A';
     }
printf("\n\n\nThe modified text is: ");
puts(s);
printf("\nThe NEW number of aA is : %d\n",counter_aA(r));
printf("The NEW number of zZ is : %d\n",counter_zZ(r));
      }
      else
      {
 if (k==l)
 {
    for(i=0; i<(strlen(s)/2); i++)
{
      if (s[i]=='a')
      s[i]='z';

      if (s[i]=='A')
      s[i]='A';

}
j=(strlen(s)-1);
     while(j>(strlen(s)/2))
     {
      if (s[j]=='z')
      s[j]='a';
      else
      if (s[j]=='Z')
      s[j]='A';
      j=j-1;
}
printf("\n\n\nThe modified text is: ");
puts(s);
printf("\nThe NEW number of aA is : %d\n",counter_aA(r));
printf("The NEW number of zZ is : %d\n",counter_zZ(r));
}
}
}

the problem asks to enter a text line an first print it then count both 'a'and'A' and 'z' and 'Z'of that line

--if the number of 'a'and'A' is > than 'z' and 'Z' replace 'a' with 'z' and 'A'with 'Z'
print the new line and count the new aA and zZ and vise versa.
--if the number of 'a'and'A' is equal(=) to 'z' and 'Z', replace 'a' with 'z' and 'A'with 'Z' until the middle of the sentence and from the end of the sentence to the middle(middle char is included) replace the 'z','Z' with 'a','A'.
Print the new sentence and the new number of 'a','A' and 'z','Z'
my code seems correct but i m told to use char*gets(char*s) instead of gets() but i don't know how.
Could you please help me ?
Thanx in advance...

[quzah]

my code seems correct but i m told to use char*gets(char*s) instead of gets() but i don't know how.

You are using gets correctly - as correct as it ever can be - but, assuming you're compiling with warnings on, you're probably actually being warned against using it. See the FAQ (click!) for more info.

Quzah.

[anduril462]

I suggest starting by fixing your code so it actually compiles without warnings. I suggest cranking the warnings all the way up while you learn to code. Some other tips:

• You need to give explicit types to all your function parameters
• Define the metrhths_aA
• Don't use gets
• Main should return an integer (preferably 0)
• Global Variables Are Bad

[junglist]

You are using gets correctly - as correct as it ever can be - but, assuming you're compiling with warnings on, you're probably actually being warned against using it. See the FAQ (click!) for more info.

Quzah.

thnx for the faq quzah...i ll read it.....
as for the warning i get 0 errors 0 warnings in code::blocks
.and again thank you...

[junglist]

I suggest starting by fixing your code so it actually compiles without warnings. I suggest cranking the warnings all the way up while you learn to code. Some other tips:

• You need to give explicit types to all your function parameters
• Define the metrhths_aA
• Don't use gets
• Main should return an integer (preferably 0)
• Global Variables Are Bad

i fixed the metrhths_aA it is counter_aA

is strpbrk() of any use in this kind of programm?

Thank you all for your answers.I'll try to read the FAQs ASAP...

[anduril462]

is strpbrk() of any use in this kind of programm?

Yes.

[quzah]

You could use it, but why? You are still going to end up calling it in a loop to get all the characters you want, and it's still going to be running a loop, so it's really more inefficient than just having a single loop of your own.


Quzah.

[anduril462]

True, though I was thinking calling it from the character after the one you just found and replaced.

[junglist]

Is there anyway getting a string without declairing the lenght of itat the begining and without dealing with programming problems?
If so do i have to make many changes in my initial code?
Thnx in advance

[MK27]

Is there anyway getting a string without declairing the lenght of itat the begining and without dealing with programming problems?

You can declare a char pointer and when you know how much space you need, use malloc():

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

int main(void) {
	char *buffer, ch;
	int sz = 4096, count = 0;

/* allocate initial memory */
	if (!(buffer = malloc(sz))) {
		puts("Out of memory!");
		return 1;
	}

/* read from stdin */
	while ((ch = getchar())) {
		if (feof(stdin)) break;
		if (count == sz-1) {	/* increase allocated memory as necessary */
			sz *= 2;
			if (!(buffer = realloc(buffer,sz))) { 
				puts("Out of memory!");
				return 1;
			}
		}
		buffer[count++] = ch;  

	}
	buffer[count] = '\0';

	printf("BUFFER CONTENTS:\n%s\n",buffer);

	free(buffer);
	return 0;
}

[CommonTater]

Is there anyway getting a string without declairing the lenght of itat the begining and without dealing with programming problems?
If so do i have to make many changes in my initial code?
Thnx in advance

The practicality, in a language that does not have native support for strings, is that you're going to have to create a character buffer someplace. There are trick you can use such as going character by character and expanding the buffer as you go (per MK27's suggestion) but ultimately you are going to have to provide memory space for it somehow.

The standard C functions getline() and getdelim() should interest you as both read from an input stream and allocate their own memory for your strings. You may also want to look at strdup() when moving and sorting... However; these functions will require you to provide pointers to strings and to fee the memory when you're done with it.

There's just no way around manual memory management in C (and that's a good thing).

[stahta01]

as for the warning i get 0 errors 0 warnings in code::blocks

Learn the name of the Compiler you are using and post the name in threads like this.
Turn on the option to increase the warning from the Compiler as suggested before.
Have the C::B display the full command line to help you learn what it is doing.
How to Set C::B to Full Command line FAQ - CodeBlocks

Tim S.

[MK27]

The standard C functions getline() and getdelim() should interest you...

Getline() and getdelim() are not standard functions (they are GNU extensions) but they are useful if you have them.

[CommonTater]

Getline() and getdelim() are not standard functions (they are GNU extensions) but they are useful if you have them.

Not just GNU... they are described in ISO TR24731-1 and 2, and are implemented in PellesC and others as part of stdio.h ... which is, by gosh, part of the standard library.

[laserlight]

they are described in ISO TR24731-1 and 2

Hence they are not (yet) part of the C standard. In fact, neither appears in WG14 N1256 (PDF), which the C standard committee's website considers the "lastest (latest?) publically available version of the standard" (though of course, it is still not officially the standard).

and are implemented in PellesC and others as part of stdio.h ... which is, by gosh, part of the standard library.

That does not mean that they are part of the standard library. It does mean that they are extensions to the standard library.