Passing values as pointers?

tbites · #1 14-Oct-2009, 10:54

Hello all,
I am new to this forum. and want to thank you for having help for coding.
I am not a mooch. I like to try my hand at my code first. Then get some help.
What I am trying to do is practice pointers to a function.
Below I compiled it but it doesnt display the length of the string?
I want to make sure I am passing the values by pointers to the function.
So that is where I am at. I do understand they have to be the same data
types. Thanks

that is a funny emoticon. had to use it

CPP / C++ / C Code:

//trying to test to see if I am passing by pointer?
//am I passing by pointer correctly it doesn't seem to work?

#include <stdio.h>
#include <string.h>
int functionFoo(char *strng, int toAdvance){ 
  int length = strlen(strng);
  return length;
}

int main(){
   int ok = 0;
   char *strng="";
   gets(strng);
   ok = functionFoo(strng, 0);
   printf("%i", ok);                             //dummy me didnt see the missing i next to % fixed
   return 0;
}

tbites · #2 14-Oct-2009, 11:28

oops found on errror but i sang my song too soon back to debug!

but am I passing my pointers right with the char string data type???

but I have another question am I passing pointer correctly in this program??
I am just wondering if I am doing it right? am IT
it works now but just because it works does that mean I am passing pointers into theprogram correctly? thanks

tbites · #3 14-Oct-2009, 12:00

hey gues I got it to work but is this the correct way to pass pointers?
I am just making sure I am passing the pointers correctly and initializing
the char string correctly????

CPP / C++ / C Code:

#include <stdio.h>
#include <string.h>
int foo(char *strng){
    
    int length = strlen(strng);
  
    return length;

}//end of foo()

int main(){
   int ok = 0;
   char *strng="";
   gets(strng);
   ok = foo(strng);
   printf("Number or character is: %i", ok);
   return 0;
}

fakepoo · #4 14-Oct-2009, 13:01

You have one big error:

CPP / C++ / C Code:

char *strng="";

This statement allocates an empty string (only enough space for the null terminating character).

If you wish to store anything into the string, you should allocate it like this:

CPP / C++ / C Code:

char strng[32]="";

This would now allow you to enter 31 characters into the string.

tbites · #5 14-Oct-2009, 13:30

hey fakepoo

that name makes me laugh!
hey thanks, I was thinking that but hey thanks a lot! for you taking the time to help me..I appreciate your expert advice..

so yu think I am passing with pointers correctly do you?

fakepoo · #6 14-Oct-2009, 13:35

Here is a general tutorial on pointers. It may answer some of your questions. If you have specific questions, feel free to post them here and we'll do our best to answer them.

tbites · #7 14-Oct-2009, 13:47

hey fakepoo thanks for the pointer ref! great

hey look at this it gives me some kind of indirection error? something about char * ??I don't know what that means? compile and run and maybe you can see what I mean? thanks

Code:

#include <stdio.h>
#include <string.h>
int foo(char *strng){
    
    int length = strlen(strng);
  
    return length;

}//end of foo()

int main(){
   int ok = 0;
   char *strng[32]={""};
   gets(strng);
   ok = foo(strng);
   printf("Number or character is: %i", ok);
   return 0;
}

fakepoo · #8 14-Oct-2009, 13:59

CPP / C++ / C Code:

char *string1 = "One way to declare a string.";
char string2[64] = "Another way to declare a string.";

int length1 = strlen(string1);
int length2 = strlen(string2);

Notice that you can either declare a char pointer (char *) or a char array (char[]). Both can be accessed and used as a char *.

tbites · #9 14-Oct-2009, 14:05

wow I tried it in mine and it works; wow man i feel so dumb
thanks so much for the explaination and your valuable time
I hope I am as good as you some day -thanks fakepoo!

so array can be used with char* since arrays are consider pointers??? is that right?

fakepoo · #10 14-Oct-2009, 14:11

Quote:

Originally Posted by tbites

so array can be used with char* since arrays are consider pointers??? is that right?

Look at the section "Pointers and arrays" on this page. It does a very good job of explaining it.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Rate This Thread
Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Functions: Passing pointers vs by reference	dlp	C++ Forum	0	05-Nov-2007 04:36
Sort an array of structures	sassy99	C Programming Language	10	15-Feb-2007 08:46
[Tutorial] Pointers in C (Part II)	Stack Overflow	C Programming Language	0	27-Apr-2005 18:36
[Tutorial] Pointers in C (Part I)	Stack Overflow	C Programming Language	1	08-Apr-2005 19:35

Passing values as pointers?

Re: noob..passing values as pointers????

So is this correct way to pass pointers?????--easy question

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????

Re: noob..passing values as pointers????