ASCII C Help, Please

bigearsbilly · 09-21-2005, 04:05 AM

oooops! didn't test

strcat changed:

Code:

#include<stdio.h>

 char firstName[512];
  char lastName[512];
  char fullName[1024];

int main()
{


   

    printf("Please enter your first name: ");
    scanf("%s", firstName);

    printf("Please enter your last name: ");
    scanf("%s", lastName);

    sprintf(fullName, "%s %s", firstName, lastName);          //This is supose to assign both the firstName[] and lastName[] string arrays to the fullName[] string array.


    printf("%s\n", fullName);


    getchar();

}

Thinking · 09-21-2005, 04:29 AM

hmm

just a little question
what does fflush(stdin); ??
fflush flushes an output buffer
but stdin is input
so it should just do nothing, not?

bigearsbilly · 09-21-2005, 05:01 AM

'tis removed.
good spot.
(cut and pasted)

InvisibleSniper · 09-21-2005, 06:06 AM

I know that when you want to put a value into a variable using scanf you need to use the & operator like:

Code:

scanf("%d", &age);

. What other data types do you need to use the & operator for when using the scanf function?

Also do I need to use the & operator for arrays when accepting string input using scanf?

bigearsbilly · 09-21-2005, 06:14 AM

for an array don't need the &
the name is the address.

e.g:
char buffer[100];

buffer same as &buffer[0]

InvisibleSniper · 09-21-2005, 06:43 AM

Quote:

Originally posted by bigearsbilly
for an array don't need the &
the name is the address.

e.g:
char buffer[100];

buffer same as &buffer[0]

So I would need the & for char, float, int and double and that's all?

I know that the & symbol before a variable like:

Code:

&myAge;

is a symbol that is reffered to as the "Address Of Operator", which is used for pointers as I have learnt this from C++. Anything I need to know about this in C or is that all?

Thank Yous For You Time

bigearsbilly · 09-21-2005, 07:30 AM

correct.

trying getting familiar with a debugger.
'gdb' with 'ddd' is particularly good. you can play about and see
what's really happening in there. It all helps gain an understanding.
you can even call functions etc.

InvisibleSniper · 09-22-2005, 12:29 AM

Have another question. What I am trying to do with the below program is to not print any of the array on the last string literal, but still have the %4s in the string.:

Code:

/*
*Trying to work out how I would print the %s, in a string. I know in C++ it will
* print if you just put it in single quotes, for example '%s'.
*
*/
#include<stdio.h>


int main()
{
    char myFirstName[15];

    printf("Please enter your name: ");

    scanf("%s", myFirstName);

    printf("\nYour first name is %s\n", myFirstName);
    printf("How do get this to print and not the array? >> '%4s' ");


    fflush(stdin);
    getchar();



}

paulsm4 · 09-22-2005, 12:33 AM

printf("How do get this to print and not the array? >> '%%4s' ");

PS:
Leaving out the "#include <string.h>" (from the earlier version, when you had "strcat()") and failing to return a value from "main()" (still in the current version) are both arguably bugs. At best, they're poor form.

The "fflush()" is harmless, but unnecessary. The C library automatically flushes any output pending on "stdout" before accepting input from "stdin". The third stream, "stderr", is always unbuffered and, consequently, never needs to be flushed.

As a previous poster suggested, the debugger (e.g. "gdb") can be your friend. On gcc, debugging support is enabled via the "-g" compiler switch.

Another good practice is to always compile with "full warnings". On gcc, this is the "-Wall" switch (actually, there are also other, even stricter switches you could add).

Here's what I got compiling your program with "-g" and "-Wall":

Quote:

cc -g -Wall xx.c
xx.c: In function `main':
xx.c:18: warning: too few arguments for format
xx.c:26: warning: control reaches end of non-void function

Wim Sturkenboom · 09-22-2005, 01:12 AM

Code:

printf("How do get this to print and not the array? >> '%4s' ");

%4s indicates that there's a parameter to print.
e.g

Code:

printf("How do get this to print and not the array? >> '%4s' ","bye bye");
// or from your code
printf("\nYour first name is %s\n", myFirstName);

Thinking · 09-22-2005, 02:08 AM

i think InivisbleSniper wanted to know this:
printf("How do get this to print and not the array? >> '\%4s' ");

in C you have to use a backslash for the %
if you do
printf("\%"); it will print the %
printf("\\"); will print a \
and so on ....

if you aren't sure ask yourself this question:
if i want to print
%4s
how does the printf function know if i want to print %4s or a string?
it's the backslash who makes the difference *g*

bigearsbilly · 09-22-2005, 03:30 AM

this?

Code:

int main(void)
{

    printf("%%4s\n");

}



$ 1
%4s
$

InvisibleSniper · 09-26-2005, 12:22 AM

Can someone please tell me where I can learn more of the "Standard ANSI C Functions". Something that is more informitive, has more discription then other tutorials?

chrism01 · 09-26-2005, 12:57 AM

here's a very good C book, includes ASCII to decimal conv table and lists+definitions of std includes eg stdio.h, strcat() etc.

InvisibleSniper · 09-26-2005, 02:01 AM

Quote:

Originally posted by chrism01
here's a very good C book, includes ASCII to decimal conv table and lists+definitions of std includes eg stdio.h, strcat() etc.

Where's the book??

Also I was wondering how do I accept user input for a "char". I mean accept user input for just one character no more and no less. I have a program that is not working because of this. It gets up to the part where the user is supose to enter a S for single or a D for double. But then it crashes, if someone could tell me how to fix this program without including any new functions that I don't know about yet, that would be very helpful.

Code:

#include<stdio.h>


int main()

{

/*This program is supose to get the title, artist, number of tracks, price and if the CD is a single or double. The program gets up to single or double and crashes./*


    char title[41] = " ";
    char artist[41] = " ";
    int numOfTracks = 0;
    float price = 0;
    char albumSinDou = " ";

    printf("Please enter the title of the CD: ");
    scanf("%[^\n]", title);
    fflush(stdin);

    printf("\nPlease enter the artist of the CD: ");
    scanf("%[^\n]", artist);


    printf("\nPlease enter the number of tracks the CD has: ");
    scanf("%d", &numOfTracks);

    printf("\nPlease enter the price of the CD: ");
    scanf("%f", &price);

    printf("\nIs this CD a single or double, please press s for single or d for double: ");
    scanf("%c", albumSinDou);

    printf("Title: %s, Artist: %s, Tracks: %d, Price: $%.2f, %c", title, artist, numOfTracks, price, albumSinDou);
    fflush(stdin);
    getchar();





}

I would only like one charachter to be accepted into the single or double variable this is why I did not make it an array.

Thank You.