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I have an assignment where I need to scan in strings from a data file (there are about 12 strings). the strings have random numbers in the middle of the words and random punctuation. i need to reprint the strings in reverse order (bottom string at the top, top string at the bottom), and remove all the numbers and punctuation.
Is it possible to scan a string in as a %s, or do I need to scan each character and assign them to the values of a string?
thanks.
Use fgets:
Of course you'll need a character array for each line from the file.Code:char buffer[20];
FILE* fpInput;
...
fgets(buffer,sizeof(buffer),fpInput);
I'd recommend using fgets to obtain the strings. I found recursion based on the success of a call to fgets an easy way to reverse the order. And the function isalpha in a simple loop through the string would be useful in determining whether or not to putchar a character.
this is what i have so far. It is just printing random symbols to the output file.
Code:#include <ctype.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
#define FILENAME "D:h4ot.txt"
#define INNAME "D:dat4.txt"
#define STRINGSIZE 50
int main( void)
{
char string1 [STRINGSIZE];
char string2 [STRINGSIZE];
char string3 [STRINGSIZE];
int k;
FILE* outfile;
outfile = fopen( FILENAME, "w" );
FILE* infile;
infile = fopen ( INNAME, "r");
while((fgets( string1, STRINGSIZE, infile)))
{
for (k=0; k<=(strlen(string1)-2); k++)
{
if (isalpha(string1[k]))
{
putchar(string2[k]);
}
}
strcat(string2, string3);
strcpy(string3, string2);
}
fprintf(outfile, "%s", string3);
return 0;
}
thanks
Let's trim this up a bit and start with something workable.It's much the same as your attempt, but ask questions about any of my changes that you didn't understand. If you need the output to go to a file, use fputc instead of putchar.Code:#include <stdio.h>
#include <ctype.h>
int main( void)
{
FILE* file = fopen ( "file.txt", "r" );
if ( file )
{
char line [ 50 ];
while ( fgets( line, sizeof line, file ) )
{
int k;
for ( k = 0; line [ k ] != '\0'; ++k )
{
if ( isalpha ( line [ k ] ) )
{
putchar ( line [ k ] );
}
}
putchar ( '\n' );
}
fclose ( file );
}
return 0;
}
You'll notice that the order is not reversed. This is why I mentioned recursion.
[Sorry for the name changes, I'm a little crusty. And you'll need to change your filename back.]
Of course it does. What did you expect it to do? First off, your buffer isn't initialized, so it has a bunch of random crap in it. Next, the first time string3 shows up in your program, you're copying it to another uninitialized buffer, and then copying that back over top of it. Then you print it to a file?Quote:
Originally Posted by andy84
How could it possibly contain something useful?
Quzah.
Dave_Sinkula , i copied your program into Turbo C++ (my compiler...it also does plain C) and created a data file called file.txt which is in the same directory as the program.
the data file looks like this:
asdf44sdf
asdfa44sdfsdfa
asd45fsadwe
ewweeer435rdf
fddfd55fdfdf
When the program runs, it doesn't come up with any errors, but it doesn't take out any of the numbers like it's supposed to either.
quzah :
I don't understand what you mean about initializing the buffer. are you saying that i should fill the string1 with all zero's? the examples in my book do it like i did, just declaring a char string1[50]
thanks for you help so far.
With this "file.txt":Quote:
Originally Posted by andy84
I get this output:Code:Pete25.33Moss
Sara78.45Bellum
Harry76Legg
Les34.5Ismoore
April109Showers
June87.345Meadows
Mae68.5Flowers
Guy56Wire
Chris66.335Craft
Slim115.25Pickens
And for me it removes the numbers from your example as well.Code:PeteMoss
SaraBellum
HarryLegg
LesIsmoore
AprilShowers
JuneMeadows
MaeFlowers
GuyWire
ChrisCraft
SlimPickens
Code:asdfsdf
asdfasdfsdfa
asdfsadwe
ewweeerrdf
fddfdfdfdf
ok, i figured that out a minute ago. everything is working now, i just need to flip the strings around (so the first one read in is at the bottom of the page, last one read in is at the top).
this is what i have so far:
Code:
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
#define FILENAME "D:h4ot.txt"
#define INNAME "D:dat4.txt"
int main( void)
{
char string1 [50];
int k;
FILE* outfile;
outfile = fopen( FILENAME, "w" );
FILE* infile;
infile = fopen ( INNAME, "r");
while(fgets( string1, sizeof(string1), infile))
{
for ( k = 0; string1 [ k ] != '\0'; ++k )
{
if (isalpha(string1[k]))
{
fputc(string1[k], outfile);
}
else
{
switch (string1[k])
{
case ',':
case '.':
fputc(string1[k], outfile); break;
default:
fputc(' ', outfile);
}
}
}
fputc('\n', outfile);
}
fprintf(outfile, "%s", string1);
return 0;
}
this is what i am thinking: have a string2 that i can concatenate (strcat) string 1 to. then i keep adding string 2 to the end of string1 each time. The only problem is that i don't know how to declare or start the string2 so that it has 50 spaces that are empty.
thanks.