I was asked to play .wav files using C language, the compiler I'm using is Devcpp.
I was trying to use the function PlaySound() as below:
PlaySound("C:/Users/wavfiles/13.1.wav", NULL, SND_FILENAME);
If I directly input the directory to the function like this, it is able to successfully play the sound.
However, I want to set the directory as a variable. I create a text file with a list of directory and extract the one that I want, then put it into PlaySound() function. Here is part of my code:
FILE *fw;
char addr[1000]
char schapter[50];
while(fgets(addr, 1000, fw) != NULL) {
if((strstr(addr, schapter)) != NULL) {
printf("\n%s", addr);
PlaySound(addr, NULL, SND_FILENAME);
}
}
In this case, the directory is assigned to addr (addr = "C:/Users/wavfiles/13.1.wav") and then I put addr into PlaySound(), but it doesn't work.
I have been stuck on this problem for a long time and cannot move on.
I would really appreciate it if anyone can give me suggestions or solutions.
Thank you.
The string returned by fgets() contains the terminal newline. You'll need to remove that to get the filename.
An easy way to do this is to use strchr() to locate the newline:
while (fgets(addr, 1000, fw) != NULL) {
char *nl = strchr(addr, '\n');
if (nl) *nl = 0;
…
}
Related
When trying to open a file with fopen(path, "2"); i get NULL on an existing path
iv'e tried to enter only the file name and it works but i want the program to write the file in the path...
Yes, i write the path with double backslashes "\\" when it's necesary.
Yes the path without doubt exists.
FILE* log;
char directory_path[PATH_LEN] = { 0 };
char directory_file[PATH_LEN] = { 0 };
//directory_path is the directory, entered by the user
//LOG_NAME is the files name without the path - "log.txt"
//#define PATH_LEN 100
printf("Folder to scan: ");
fgets(directory_path, PATH_LEN, stdin);
directory_path[strlen(directory_path) - 1] = 0;
//this section connects the path with the file name.
strcpy(directory_file, directory_path);
strcat(directory_file, "\\");
strcat(directory_file, LOG_NAME);
if ((log = fopen(directory_file, "w")) == NULL)
{
printf("Error");
}
My program worked until i tried to write into a file in order to create a log file. This means that the path is correct without doubt.
Can anyone tell me the problem here?
You have several issues in your code:
For one, fopen(path, "2"); is not valid.
The mode argument needs to include one of a, r, and w and can optionally include b or +.
As another thing, directory_path[strlen(directory_path) - 1] = 0; may truncate the end of your path (if it's over PATH_LEN characters long).
There also may be a possible issue with buffer overflow due to the fact that you copy a string to a buffer of the same size and then concatenate two other strings to it. Therefore, you should change this line:
char directory_file[PATH_LEN] = { 0 };
to this:
char directory_file[PATH_LEN+sizeof(LOG_NAME)+1] = { 0 };
To debug this issue, you should print the string entered and ask for confirmation before using it (wrap this in #ifdef DEBUG).
I need to say that i am Newbie at C and i only wrote about 100-150 lines of code in C.
I need to read a .properties file with entries like the following:
Value1 = Hello
Value2 = Bye
I would like to get to the Values like this:
bla.getValue("Value1");
So i can work with it like this:
foo = bla.getValue("Value1");
bar = bla.getValue("Value2");
printf("%s - %s",foo,bar);
I don't need them for anything else, than printing them to the screen.
I found two questions here, which went into the right direction, but they couldn't help me in my task:
How to read configuration/properties file in C?
Properties file library for C (or C++)
I tried multiple of the answers of the thread above, but either way my compiler(minGW) doesn't like one of these lines:
using foo::bar;
or
using namespace foo;
When i try to compile my code, i get an error saying:
error: unknown type name 'using'
This is the code where i tried to implement the given solution of the thread above:
#include <windows.h>
#include <stdio.h>
#include <string.h>
using platformstl::properties_file;
int WINAPI WinMain(HINSTANCE a,HINSTANCE b,LPSTR c,int d)
{
char *tPath, *tWindow;
char *search = " ";
tWindow = strtok(c, search);
tPath = strtok(NULL, search);
properties_file properties("%s",tPath);
properties::value_type value1 = properties["Value1"];
properties::value_type value2 = properties["Value2"];
printf("Window: %s; Path: %s; %s %s",tWindow,tPath,value0,value1);
}
I use a WinMain, because the programm is about finding an open Window. I haven't included those parts of the code, because they are irrelevant for my question and worked completely fine. The strtok(); parts are working fine for me too. I need them, because the title of the window to find and the Path of the properties file are both given as commandline arguments:
programm.exe windowtitle path/to/properties/file
As i tried with other answers, which told me to load some libraries, i got to a point, where the needed libraries didn't contain the needed header files. Some of the libraries are even for c++, which i have a restriction on, so i can't use it.
I hope that made things a little clearer, as you may know that i am not used to ask questions here. :)
I solved my Problem with a big Workaround.
This is my final code:
if(vn != NULL){
for(i = 0; i < 1; i++){
if(fgets(temp, BUF, vn) == NULL){
printf("Line is empty");
return 2;
}
}
if(fgets(puffer, BUF, vn) == NULL){
printf("Line is empty");
return 2;
}
tVariable = strtok(puffer, find);
tValue = strtok(NULL, find);
}else {
printf("Unable to read File");
return 2;
}
I just read the second Line of the given file and cut it at the = sign.
I know, that i need to read the second line, because the Property i need is always found in the second line of the .properties file.
I now have my wanted Value in tValue, so i can use it to print it out with printf("%s", tValue).
I'm learning to use libcurl in C. To start, I'm using a randomized list of accession names to search for protein sequence files that may be found hosted here. These follow a set format where the first line is a variable length (but which contains no information I'm trying to query) then a series of capitalized letters with a new line every sixty (60) characters (what I want to pull down, but reformat to eighty (80) characters per line).
I have the call itself in a single function:
//finds and saves the fastas for each protein (assuming on exists)
void pullFasta (proteinEntry *entry, char matchType, FILE *outFile) {
//Local variables
URL_FILE *handle;
char buffer[2] = "", url[32] = "http://www.uniprot.org/uniprot/", sequence[2] = "";
//Build full URL
/*printf ("u:%s\nt:%s\n", url, entry->title); /*This line was used for debugging.*/
strcat (url, entry->title);
strcat (url, ".fasta");
//Open URL
/*printf ("u:%s\n", url); /*This line was used for debugging.*/
handle = url_fopen (url, "r");
//If there is data there
if (handle != NULL) {
//Skip the first line as it's got useless info
do {
url_fread(buffer, 1, 1, handle);
} while (buffer[0] != '\n');
//Grab the fasta data, skipping newline characters
while (!url_feof (handle)) {
url_fread(buffer, 1, 1, handle);
if (buffer[0] != '\n') {
strcat (sequence, buffer);
}
}
//Print it
printFastaEntry (entry->title, sequence, matchType, outFile);
}
url_fclose (handle);
return;
}
With proteinEntry being defined as:
//Entry for fasta formatable data
typedef struct proteinEntry {
char title[7];
struct proteinEntry *next;
} proteinEntry;
And the url_fopen, url_fclose, url_feof, url_read, and URL_FILE code found here, they mimic the file functions for which they are named.
As you can see I've been doing some debugging with the URL generator (uniprot URLs follow the same format for different proteins), I got it working properly and can pull down the data from the site and save it to file in the proper format that I want. I set the read buffer to 1 because I wanted to get a program that was very simplistic but functional (if inelegant) before I start playing with things, so I would have a base to return to as I learned.
I've tested the url_<function> calls and they are giving no errors. So I added incremental printf calls after each line to identify exactly where the bus error is occurring and it is happening at return;.
My understanding of bus errors is that it's a memory access issue wherein I'm trying to get at memory that my program doesn't have control over. My confusion comes from the fact that this is happening at the return of a void function. There's nothing being read, written, or passed to trigger the memory error (as far as I understand it, at least).
Can anyone point me in the right direction to fix my mistake please?
EDIT: As #BLUEPIXY pointed out I had a potential url_fclose (NULL). As #deltheil pointed out I had sequence as a static array. This also made me notice I'm repeating my bad memory allocation for url, so I updated it and it now works. Thanks for your help!
If we look at e.g http://www.uniprot.org/uniprot/Q6GZX1.fasta and skip the first line (as you do) we have:
MNAKYDTDQGVGRMLFLGTIGLAVVVGGLMAYGYYYDGKTPSSGTSFHTASPSFSSRYRY
Which is a 60 characters string.
When you try to read this sequence with:
//Grab the fasta data, skipping newline characters
while (!url_feof (handle)) {
url_fread(buffer, 1, 1, handle);
if (buffer[0] != '\n') {
strcat (sequence, buffer);
}
}
The problem is sequence is not expandable and not large enough (it is a fixed length array of size 2).
So make sure to choose a large enough size to hold any sequence, or implement the ability to expand it on-the-fly.
I have the following Config.cfg
[DD]
user=**
password=***
database=***
IPServidor=****
port=***
[Controller]
Control1=8
Temp=5
Hum=7
Link=8
Volt=9
[Controller]
Control2=10
Temp=5
Hum=7
Link=8
Volt=9
I would like to read the values of the controllers only and print them to the screen like
Controller_8: 5,7,8,9
I do not want to use libconfig or glib because I have problem with undefined functions. I did the installation, I have the headers but I do not know why it does not work. So I want another solution. My first thought is with the usage of strchr to find the lines which I want (to ignore [DD] table in my case) and with the usage of strtok to get only the values of temp,hum,link,volt
char buffer1[100];
FILE *f = fopen("/home/pi/Desktop/Config.cfg","r");
while(fgets(buffer1, sizeof(buffer1), f))
{
printf("%s",buffer1);
char *pos1 = strchr(buffer1,'Controller');
if (pos1)
{
item = strtok (buffer1,"Control");
printf("Results: %s\n", buffer1);
}
}
The above code is not correct. Is just a thought. Is there any better way?
Don't try parsing ini files, use some existing library.
Ini file parsing is included in a number of "frameworks", for instance in Gtk+ or on Windows. If you can't access those, you can still use some standalone library, for instance: http://ndevilla.free.fr/iniparser/
I'm making a small console-based rpg, to brush up on my programming skills.
I am using structures to store character data. Things like their HP, Strength, perhaps Inventory down the road. One of the key things I need to be able to do is load and save characters. Which means reading and saving structures.
Right now I'm just saving and loading a structure with first name and last name, and attempting to read it properly.
Here is my code for creating a character:
void createCharacter()
{
char namebuf[20];
printf("First Name:");
if (NULL != fgets(namebuf, 20, stdin))
{
char *nlptr = strchr(namebuf, '\n');
if (nlptr) *nlptr = '\0';
}
strcpy(party[nMember].fname,namebuf);
printf("Last Name:");
if (NULL != fgets(namebuf, 20, stdin))
{
char *nlptr = strchr(namebuf, '\n');
if (nlptr) *nlptr = '\0';
}
strcpy(party[nMember].lname,namebuf);
/*Character created, now save */
saveCharacter(party[nMember]);
printf("\n\n");
loadCharacter();
}
And here is the saveCharacter function:
void saveCharacter(character party)
{
FILE *fp;
fp = fopen("data","a");
fwrite(&party,sizeof(party),1,fp);
fclose(fp);
}
and the loadCharacter function
void loadCharacter()
{
FILE *fp;
character tempParty[50];
int loop = 0;
int count = 1;
int read = 2;
fp= fopen("data","r");
while(read != 0)
{
read=fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp);
printf("%d. %s %s\n",count,tempParty[loop].fname,tempParty[loop].lname);
loop++;
count++;
}
fclose(fp);
}
So the expected result of the program is that I input a name and last name such as 'John Doe', and it gets appended to the data file. Then it is read in, maybe something like
1. Jane Doe
2. John Doe
and the program ends.
However, my output seems to add one more blank structure to the end.
1. Jane Doe
2. John Doe
3.
I'd like to know why this is. Keep in mind I'm reading the file until fread returns a 0 to signify it's hit the EOF.
Thanks :)
Change your loop:
while( fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp) )
{
// other stuff
}
Whenever you write file reading code ask yourself this question - "what happens if I read an empty file?"
You have an algorithmic problem in your loop, change it to:
read=fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp);
while(read != 0)
{
//read=fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp);
printf("%d. %s %s\n",count,tempParty[loop].fname,tempParty[loop].lname);
loop++;
count++;
read=fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp);
}
There are ways to ged rid of the double fread but first get it working and make sure you understand the flow.
Here:
read=fread(&tempParty[loop],sizeof(tempParty[loop]),1,fp);
printf("%d. %s %s\n",count,tempParty[loop].fname,tempParty[loop].lname);
You are not checking whether the read was successful (the return value of fread()).
while( 1==fread(&tempParty[loop],sizeof*tempParty,1,fp) )
{
/* do anything */
}
is the correct way.
use fopen("data","rb")
instead of fopen("data","r") which is equivalent to fopen("data","rt")
You've got the answer to your immediate question but it's worth pointing out that blindly writing and reading whole structures is not a good plan.
Structure layouts can and do change depending on the compiler you use, the version of that compiler and even with the exact compiler flags used. Any change here will break your ability to read files saved with a different version.
If you have ambitions of supporting multiple platforms issues like endianness also come into play.
And then there's what happens if you add elements to your structure in later versions ...
For robustness you need to think about defining your file format independently of your code and having your save and load functions handle serialising and de-serialising to and from this format.