simple output input ....

[chutsu@gmail.com]

Hi
Ok...I got a problem in reading a file containning information, and
trying to send it to a function...
the file containing information has format:
Gas 10000 Home Gas Meter
Electricity 3000 Home Electricity Meter
Flight 8000 Holiday Abroad
Flight 1000 Long Weekend
Car 1250 Own Car (10000 miles)
Car 500 Holiday Hire Car

I would like to put the first column to be stored in an array called -
char fuel [ ]
second column - double amount
third column - char description [ ]

the first and second will be used by a fuction called double co2(char
fuel [ ], double amount)
and the third will be stored in the int main ....

Second Question...Can you return 2 values from a function double
co2(char fuel [ ], double amount)??

Thanks
Chris

[Malcolm McLean]

Re: simple output input ....


<chutsu@gmail.c omwrote in message
news:1179094788 .034227.184210@ u30g2000hsc.goo glegroups.com.. .

Hi
Ok...I got a problem in reading a file containning information, and
trying to send it to a function...
the file containing information has format:
Gas 10000 Home Gas Meter
Electricity 3000 Home Electricity Meter
Flight 8000 Holiday Abroad
Flight 1000 Long Weekend
Car 1250 Own Car (10000 miles)
Car 500 Holiday Hire Car
>
I would like to put the first column to be stored in an array called -
char fuel [ ]
second column - double amount
third column - char description [ ]
>
the first and second will be used by a fuction called double co2(char
fuel [ ], double amount)
and the third will be stored in the int main ....
>
Second Question...Can you return 2 values from a function double
co2(char fuel [ ], double amount)??
>

Call fgets() to read the input, one line at a time.
Once you've got the line into a temporary buffer, you need to break it up.
This is actually quite fiddly, but not conceptually difficult.
You can get the first word by reading until you hit a space character, the
number by calling strtol(), and then the end pointer that you pass to strtol
gives you the remainder of the line. However you should also deal with any
unexpected inputs.
Another way is to use fscanf(). However this is very easy to use unsafely.
--
Free games and programming goodies.

http://www.personal.leeds.ac.uk/~bgy1mm

[Jim Barlow]

Re: simple output input ....

chutsu@gmail.co m wrote:

Hi
Ok...I got a problem in reading a file containning information, and
trying to send it to a function...
the file containing information has format:
Gas 10000 Home Gas Meter
Electricity 3000 Home Electricity Meter
Flight 8000 Holiday Abroad
Flight 1000 Long Weekend
Car 1250 Own Car (10000 miles)
Car 500 Holiday Hire Car
>
I would like to put the first column to be stored in an array called -
char fuel [ ]
second column - double amount
third column - char description [ ]
>
the first and second will be used by a fuction called double co2(char
fuel [ ], double amount)
and the third will be stored in the int main ....
>
Second Question...Can you return 2 values from a function double
co2(char fuel [ ], double amount)??
>
Thanks
Chris
>

Response to the Second Question:
See K&R chapter 1, section 8, page 29

"When the name of an array is used as an argument, the value
passed to the function is the location or address of the beginning of
the array - there is no copying of array elements. By subscripting this
value, the function can access and alter any argument of the array."

Your function will alter the values in the original array.

[Keith Thompson]

Re: simple output input ....

Jim Barlow <formaldehyde@c harter.netwrite s:
[...]

See K&R chapter 1, section 8, page 29
>
"When the name of an array is used as an argument, the value
passed to the function is the location or address of the beginning of
the array - there is no copying of array elements. By subscripting
this value, the function can access and alter any argument of the
array."

Which is actually (as I keep repeating) a special case of a more
general rule. Whenever an array name (more generally, an expression
of array type) is used, its value is implicitly converted to a pointer
to its first element, *unless* it's the operand of a unary "&" or
"sizeof" operator, or it's a string literal used to initialize a
character array.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[guru.jois@gmail.com]

Re: simple output input ....

On May 14, 3:19 am, "chu...@gmail.c om" <chu...@gmail.c omwrote:

Hi
Ok...I got a problem in reading a file containning information, and
trying to send it to a function...
the file containing information has format:
Gas 10000 Home Gas Meter
Electricity 3000 Home Electricity Meter
Flight 8000 Holiday Abroad
Flight 1000 Long Weekend
Car 1250 Own Car (10000 miles)
Car 500 Holiday Hire Car
>
I would like to put the first column to be stored in an array called -
char fuel [ ]
second column - double amount
third column - char description [ ]
>
the first and second will be used by a fuction called double co2(char
fuel [ ], double amount)
and the third will be stored in the int main ....
>
Second Question...Can you return 2 values from a function double
co2(char fuel [ ], double amount)??
>
Thanks
Chris

If the box is Unix.. use

cut -f1 -d' ' to access first column,
In general
cut -fx -d' ' to access xth column,

[chutsu@gmail.com]

Re: simple output input ....

ok so far:

#include <stdio.h>


double co2(char fuel[], double amount){



}



//Main program starts here
int main ()
{
char fuel[20];
double amount;
double Total_Sum=0;
char description[40];
char answer;
char ch;
int i;
int y=0;
FILE * fptr;
fptr = fopen("info.txt ", "r");
ch = getc(fptr);

//Displays the programs function
printf("\n\n");
printf("This program is designed to caculate the net CO2 emissions
\n");
printf("- Using the information listed in a file\n");
printf("- Read and analyse the information\n") ;
printf("- Give total CO2 emission in kg and 'rations'\n");
printf("- Provide a breakdown of the emissions\n");
printf("- Make use of the 'srncmp' function\n\n");

//Continue program?
printf("Do you what to start the program?(Y/N) ");
scanf(" %c",&answer);
printf("\n");

//If Yes?
if(answer='Y'){
while ( ch != EOF){
fscanf(fptr,"%1 9s %lf %39 [^\n]",fuel , &amount,
description);
}
}


return 0;
}

is my fscanf right?? cause I don't think its quite working....

[Barry Schwarz]

Re: simple output input ....

On 14 May 2007 15:00:40 -0700, "chutsu@gmail.c om" <chutsu@gmail.c om>
wrote:

>ok so far:
>
>#include <stdio.h>
>
>
>double co2(char fuel[], double amount){
>
>
>
>}
>
>
>
>//Main program starts here
>int main ()
>{
> char fuel[20];
> double amount;
> double Total_Sum=0;
> char description[40];
> char answer;
> char ch;
> int i;
> int y=0;
> FILE * fptr;
> fptr = fopen("info.txt ", "r");
> ch = getc(fptr);
>
> //Displays the programs function
> printf("\n\n");
> printf("This program is designed to caculate the net CO2 emissions
>\n");
> printf("- Using the information listed in a file\n");
> printf("- Read and analyse the information\n") ;
> printf("- Give total CO2 emission in kg and 'rations'\n");
> printf("- Provide a breakdown of the emissions\n");
> printf("- Make use of the 'srncmp' function\n\n");
>
> //Continue program?
> printf("Do you what to start the program?(Y/N) ");
> scanf(" %c",&answer);
> printf("\n");
>
> //If Yes?
> if(answer='Y'){
> while ( ch != EOF){
> fscanf(fptr,"%1 9s %lf %39 [^\n]",fuel , &amount,
>description) ;
> }
> }
>
>
> return 0;
>}
>
>is my fscanf right?? cause I don't think its quite working....

I don't think so. The third % needs an 's' somewhere to tell it to
extract a string.


Remove del for email

[mark_bluemel@pobox.com]

Re: simple output input ....

On 13 May, 23:19, "chu...@gmail.c om" <chu...@gmail.c omwrote:

Hi
Ok...I got a problem in reading a file containning information, and
trying to send it to a function...
the file containing information has format:
Gas 10000 Home Gas Meter
Electricity 3000 Home Electricity Meter
Flight 8000 Holiday Abroad
Flight 1000 Long Weekend
Car 1250 Own Car (10000 miles)
Car 500 Holiday Hire Car

Your format is unclear - is it truly columnar data, where each "field"
occupies a specific range of character positions, or is it blank
delimited?

Either way, I'd not use scanf, fscanf or fgets followed by sscanf -
IMHO the whole family of functions is the spawn of satan...

I'm not going to post a solution, as this smells like homework.

On the question of "Can you return 2 values from a function" - the
answer is simply "no". What are you actually trying to do here?

[mark_bluemel@pobox.com]

Re: simple output input ....

On 15 May, 02:10, Barry Schwarz <schwa...@doezl .netwrote:

On 14 May 2007 15:00:40 -0700, "chu...@gmail.c om" <chu...@gmail.c om>
wrote:

....

fscanf(fptr,"%1 9s %lf %39 [^\n]",fuel , &amount, description);

....

is my fscanf right?? cause I don't think its quite working....

I don't think so. The third % needs an 's' somewhere to tell it to
extract a string.

Nope, it needs the space removing between the 39 and the '['...

[mark_bluemel@pobox.com]

Re: simple output input ....

On 14 May, 23:00, "chu...@gmail.c om" <chu...@gmail.c omwrote:

ok so far:
>
#include <stdio.h>
>
double co2(char fuel[], double amount){
>
}
>
//Main program starts here
int main ()
{
char fuel[20];
double amount;
double Total_Sum=0;
char description[40];
char answer;
char ch;
int i;
int y=0;
FILE * fptr;
fptr = fopen("info.txt ", "r");
ch = getc(fptr);
>
//Displays the programs function
printf("\n\n");
printf("This program is designed to caculate the net CO2 emissions
\n");
printf("- Using the information listed in a file\n");
printf("- Read and analyse the information\n") ;
printf("- Give total CO2 emission in kg and 'rations'\n");
printf("- Provide a breakdown of the emissions\n");
printf("- Make use of the 'srncmp' function\n\n");
>
//Continue program?
printf("Do you what to start the program?(Y/N) ");
scanf(" %c",&answer);
printf("\n");
>
//If Yes?
if(answer='Y'){
while ( ch != EOF){

And how would this occur?

fscanf(fptr,"%1 9s %lf %39 [^\n]",fuel , &amount,
description);
}
}
>
return 0;
>
}
>
is my fscanf right?? cause I don't think its quite working....

remove the space after 39...

[Bart van Ingen Schenau]

Re: simple output input ....

chutsu@gmail.co m wrote:

ok so far:
>
#include <stdio.h>
>
>
double co2(char fuel[], double amount){
>
>
>
}
>
>
>
//Main program starts here
int main ()
{
char fuel[20];
double amount;
double Total_Sum=0;
char description[40];
char answer;
char ch;
int i;
int y=0;
FILE * fptr;
fptr = fopen("info.txt ", "r");
ch = getc(fptr);
>
//Displays the programs function
printf("\n\n");
printf("This program is designed to caculate the net CO2 emissions
\n");
printf("- Using the information listed in a file\n");
printf("- Read and analyse the information\n") ;
printf("- Give total CO2 emission in kg and 'rations'\n");
printf("- Provide a breakdown of the emissions\n");
printf("- Make use of the 'srncmp' function\n\n");
>
//Continue program?
printf("Do you what to start the program?(Y/N) ");
scanf(" %c",&answer);
printf("\n");
>
//If Yes?
if(answer='Y'){

This line contains an error, even though the compiler may not have
warned about it.
In C and C++, the =-sign *always* means assignment, regardless of the
context where it is used.
To test for equality, you need
if (answer == 'Y') {

If you also want to accept a lower-case y, you need to make explicit
provisions for it.
For example:
if (toupper(answer ) == 'Y') {
or
if ((answer == 'Y') || (answer == 'y')) {

while ( ch != EOF){
fscanf(fptr,"%1 9s %lf %39 [^\n]",fuel , &amount,

As others already noted, you must remove the space between 39 and [.

description);
}
}
>
>
return 0;
}
>
is my fscanf right?? cause I don't think its quite working....

The first one is (but the test following it is wrong), but the second
isn't.

Bart v Ingen Schenau
--
a.c.l.l.c-c++ FAQ: http://www.comeaucomputing.com/learn/faq
c.l.c FAQ: http://www.eskimo.com/~scs/C-faq/top.html
c.l.c++ FAQ: http://www.parashift.com/c++-faq-lite/

[CBFalconer]

Re: simple output input ....

"chutsu@gmail.c om" wrote:

>

.... snip ...

>
Second Question...Can you return 2 values from a function double
co2(char fuel [ ], double amount)??

Sure, if you collect them into a suitable struct.

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