File I/O problems!!! Help!!!

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  1. #1
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    Question File I/O problems!!! Help!!!

    I cannot understand files I/O, I have the pseudo-code for the program and some code I tried, but I cannot ge it. Could you help me please?

    *The input file is read character into an array. The array is a large array of 200 characters, and acts as temporary storage before being output after modification to a new file.

    *The output file is written starting from the character at the end of the array, and taking characters from the array in reverse order until the start of the array is reached. Counter is used to keep track of where the read/write is currently accessing the array.

    * Create an input text file using Windows notepad

    #include <stdio.h>



    void main()
    {
    // Initialise array of total 200 for characters
    char name[200];

    // Initialise single character for each read/write
    FILE *f_input;

    // Initialise variable for counter to zero
    int counter=0

    // Open input file
    FILE *f_input = fopen("FILE.TXT", "r");


    // While not at end of file (loop start)
    while (f_input==NULL);

    // read single character from input file
    fget(f_input);

    // Store character into array [counter]

    // Increment counter by one
    count=count+1
    // End of loop code



    // Close input file
    fclose(f_input);
    }


    // Decrement counter by one (This moves counter back one position to end of array)
    counter=counter-1

    // Open output file (different filename to input file)
    FILE *f_output

    // While counter is greater than zero (loop start)
    While (count=>0)

    // Get current character at array [counter]

    // Write this single character to output file
    fput(
    // Decrement counter by one
    counter=counter-1

    // End of loop code

    Close output file
    fclose(f_output);

    // End
    }

  2. #2
    ATH0 quzah's Avatar
    Join Date
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    Posts
    14,826
    Well you started off wrong:

    > void main()

    Never use void main.

    // Initialise single character for each read/write
    FILE *f_input;

    // Initialise variable for counter to zero
    int counter=0

    // Open input file
    FILE *f_input = fopen("FILE.TXT", "r");
    Why are you creating two instances of 'f_input'?

    Quzah.
    Hope is the first step on the road to disappointment.

  3. #3
    and the hat of wrongness Salem's Avatar
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    > // While not at end of file (loop start)
    while (f_input==NULL);

    // read single character from input file
    fget(f_input);


    The code for reading each line of a file is
    Code:
    while ( fgets( name, sizeof(name), f_input ) != NULL ) {
        // do something with name
    }

  4. #4
    Unregistered
    Guest
    There is something wrong with the code, it just stops.......right after i have enter path for the file name, say artists.txt

    which has the following inside.
    India Arie CD 3/27/2001 Motown 15.99 india.jpg Recent newcomer to the music
    Jill Scott CD 7/18/2000 Hidden Beach 16.99 jill.jpg Scott is a modern R&B singer from Philadelphia
    Maxwell ? Cassette 8/21/2001 Columbia 17.99 Maxwell.jpg soul singer Maxwell (his middle name) had to suffer the ignominy of his record company sitting on his debut album

    please help, i am this far and now am stuck.

    Code:
    /************************************************************/
    // Preprocessor Directives
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    #define SUCCESSFUL		1	// Return value
    #define FAILED			0	// Return value
    #define MAX_STR_SIZE	256	// Max string/filename size
    #define MIN_FORMAT		8	// Max minimum format fields
    #define MAX_ARTISTS		100	// Max artists allowed in data file
    #define FIELDS_COMPLETE	2	// Return value for successful consecutive 
    #define THREE_FIELDS	3	// Return value for 3 fields successfully read
    
    
    /************************************************************/
    // Global Declarations
    
    typedef struct
    	{
    	 char	*cpFormat;
    	 char	*cpDate;
    	 char	*cpLabel;
    	 float	fCost;
    	} LABEL;								// Artist label-related info
    
    typedef struct
    	{
    	 char	*cpFirstName;
    	 char	*cpLastName;
    	 LABEL	laLabel;
    	 char	*cpImageFile;
    	 char	*cpBio;							// Artist info
    	} ARTIST;
    
    char gcFileName[MAX_STR_SIZE]	= {' '};	// Stores file name
    int giArtistQty					= 0;		// Artist quantity in data file
    
    
    /************************************************************/
    // Prototype Declarations
    int getFile();
    void processFile(ARTIST *);
    void renderHTML(ARTIST *);
    
    
    /************************************************************/
    // Main Function
    void main(){
    	
    	// Local Declarations
    	ARTIST *arList = NULL;
    	
    	// Statements
    	if(getFile() == SUCCESSFUL){
    		arList = (ARTIST *)malloc(sizeof(ARTIST)*giArtistQty);
    		processFile(arList);
    		renderHTML(arList);
    	}// if
    }
    
    /************************************************************/
    // Function Definitions
    /*----------------------------------------
    Name	: getFile
    Comments: Validates the format of the file
    Return	: integer
    ----------------------------------------*/
    int getFile(){
    
    	// Local Declarations
    	//char cRead		= ' ';	// Stores char for reading
    	char cCheck			= ' ';	// Stores char for checking
    	int c				= 0;	// Counter
    	FILE *fpDataFile	= NULL;	// FILE structure
    	int iDataRead		= 0;	// Counter
    	char *cpTemp		= NULL;	// Temp string storage
    	char cTemp			= ' ';
    	float fTemp			= 0;
    
    	// Statements
    	printf("\nEnter the path and file name and press <ENTER> : ");
    	scanf("%s", gcFileName);
    	fpDataFile = fopen(gcFileName, "r");
    	if(fpDataFile == NULL){
    		printf("\n\n\aERROR:	File does not exist.");
    		return FAILED;
    	}
    	
    	cpTemp = (char *)malloc(sizeof(char)*MAX_STR_SIZE);
    
    	do{
    		iDataRead = fscanf(fpDataFile,"%s %s %s %s", cpTemp,cpTemp,cpTemp,cpTemp);
    		if(iDataRead == EOF && c == 0){
    			printf("\n\n\aERROR:	File is empty.");
    			return FAILED;
    		}
    
    		iDataRead = fscanf(fpDataFile,"%s %c %f", cpTemp,cTemp,fTemp);
    		if(iDataRead != THREE_FIELDS && iDataRead != EOF){
    			
    			do{
    				iDataRead = fscanf(fpDataFile,"%s %c %f", cpTemp,cTemp,fTemp);
    			} while(iDataRead != THREE_FIELDS && iDataRead != EOF && cTemp != '\n');
    		
    			if(cTemp == '\n'){
    				printf("\n\n\aERROR:	File contents improperly formatted.");
    				return FAILED;
    			}
    		}
    		if(iDataRead != EOF){
    			do{
    				cCheck = cTemp;
    				iDataRead = fscanf(fpDataFile, "%s%c", cpTemp, cTemp);
    			}while(cTemp != '\n' && iDataRead != EOF);
    			c++;
    			if(c >= MAX_ARTISTS){
    				printf("\n\n\aERROR:	File cannot contain data for more than %d artists.", MAX_ARTISTS);
    				return FAILED;
    			}// if
    		}// if
    	} while(iDataRead != EOF);
    	giArtistQty = (cCheck == '\n')?(c-1):c;
    	fclose(fpDataFile);
    	free(cpTemp);
    	return SUCCESSFUL;
    }
    
    
    /*----------------------------------------
    Name	: processFile
    Comments: Stores data from file into structure
    Return	: void
    ----------------------------------------*/
    void processFile(ARTIST *arList){
    
    	// Local Declarations
    	char *cpTemp1		= NULL;	// Temp string storage
    	char *cpTemp2		= NULL;	// Temp string storage
    	FILE *fpDataFile	= NULL;	// FILE pointer
    	int a				= 0;	// Counter
    	char cChar			= ' ';	// Temp character storage
    
    	// Statements
    	cpTemp1 = (char *)malloc(sizeof(char)*MAX_STR_SIZE);
    	cpTemp2 =	(char *)malloc(sizeof(char)*MAX_STR_SIZE);
    	fpDataFile = fopen(gcFileName, "r");
    
    	for(a=0;a<giArtistQty;a++){
    		
    		fscanf(fpDataFile, "%s", cpTemp1);
    		(arList+a)->cpFirstName = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp1))+1));
    		*( (arList+a)->cpFirstName ) = '\0';
    		strcat( (arList+a)->cpFirstName, cpTemp1);
    		
    		fscanf(fpDataFile, "%s", cpTemp1);
    		(arList+a)->cpLastName = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp1))+1));
    		*( (arList+a)->cpLastName ) = '\0';
    		if(*cpTemp1 != '?'){
    			strcat( (arList+a)->cpLastName, cpTemp1 );
    		}	
    		
    		fscanf(fpDataFile, "%s", cpTemp1);
    		(arList+a)->laLabel.cpFormat = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp1))+1));
    		*( (arList+a)->laLabel.cpFormat ) = '\0';
    		strcat( (arList+a)->laLabel.cpFormat, cpTemp1);
    		
    		fscanf(fpDataFile, "%s", cpTemp1);
    		(arList+a)->laLabel.cpDate = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp1))+1));
    		*( (arList+a)->laLabel.cpDate ) = '\0';
    		strcat( (arList+a)->laLabel.cpDate, cpTemp1);
    
    		*cpTemp2 = '\0';
    		if(fscanf(fpDataFile, "%s %f", cpTemp1, &((arList+a)->laLabel.fCost)) 
    != FIELDS_COMPLETE){
    			do{
    				strcat(cpTemp2, cpTemp1);
    				strcat(cpTemp2, " ");
    			}while(fscanf(fpDataFile, "%s %f", cpTemp1, 
    &((arList+a)->laLabel.fCost)) != FIELDS_COMPLETE);
    		}// if
    		strcat(cpTemp2, cpTemp1);
    		(arList+a)->laLabel.cpLabel = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp2))+1));
    		*( (arList+a)->laLabel.cpLabel ) = '\0';
    		strcat( (arList+a)->laLabel.cpLabel, cpTemp2 );
    		
    		fscanf(fpDataFile, "%s", cpTemp1);
    		(arList+a)->cpImageFile = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp1))+1));
    		*( (arList+a)->cpImageFile ) = '\0';
    		strcat( (arList+a)->cpImageFile, cpTemp1 );
    
    		*cpTemp2 = '\0';
    		if(fscanf(fpDataFile, "%s%c", cpTemp1, &cChar) == FIELDS_COMPLETE && 
    cChar != '\n'){
    			do{
    				strcat(cpTemp2, cpTemp1);
    				strcat(cpTemp2, " ");
    			}while(fscanf(fpDataFile, "%s%c", cpTemp1, &cChar) != EOF && cChar 
    != '\n');
    		}
    		strcat(cpTemp2, cpTemp1);
    		(arList+a)->cpBio = (char 
    *)malloc(sizeof(char)*((strlen(cpTemp2))+1));
    		*((arList+a)->cpBio) = '\0';
    		strcat( (arList+a)->cpBio, cpTemp2 );
    		
    	}// for
    
    	fclose(fpDataFile);
    	free(cpTemp2);
    	free(cpTemp1);
    
    }
    
    
    
    /*----------------------------------------
    Name	: renderHTML
    Comments: Creates HTML pages from artist data
    Return	: void
    ----------------------------------------*/
    void renderHTML(ARTIST *arList){
    
    	// Local Declarations
    	int	a				= 0;	// Counter
    	FILE *fpHTML		= NULL;	// FILE pointer
    	FILE *fpIndex		= NULL;	// FILE pointer
    	char *cpFileName	= NULL;	// HTML file name
    
    	// Statements
    	cpFileName = (char *)malloc(sizeof(char)*MAX_STR_SIZE);
    	fpIndex = fopen("index.html", "w");
    	fprintf(fpIndex,"<html>\n<head>\n<title>Music Artists</title>\n</head>\n<body>\n");
    	fprintf(fpIndex,"<h1 align=\"center\"><u>Music Artists</u></h1>\n");
    	fprintf(fpIndex,"<p align=\"left\">Make your selection from the list below:</p>\n<ul>\n");
    
    	for(a = 0;a < giArtistQty;a++){
    		
    		*cpFileName = '\0';
    		strcat(cpFileName, (arList+a)->cpFirstName);
    		strcat(cpFileName, "_");
    		strcat(cpFileName, (arList+a)->cpLastName);
    		strcat(cpFileName, ".html");
    		fpHTML = fopen(cpFileName, "w");
    		fprintf(fpHTML,"<html>\n<head>\n<title>%s %s</title>\n</head>\n<body>\n",(arList+a)->cpFirstName,(arList+a)->cpLastName);
    		fprintf(fpHTML,"<img SRC=\"%s\" BORDER=0 height=170 width=170>\n",(arList+a)->cpImageFile);
    		free((arList+a)->cpImageFile);
    		fprintf(fpHTML,"<br><b>Name</b>: %s %s\n",(arList+a)->cpFirstName,(arList+a)->cpLastName);
    		fprintf(fpHTML,"<br><b>Format</b>: %s\n", 
    (arList+a)->laLabel.cpFormat);
    		free((arList+a)->laLabel.cpFormat);
    		fprintf(fpHTML,"<br><b>Release Date</b>: %s\n",(arList+a)->laLabel.cpDate);
    		free((arList+a)->laLabel.cpDate);
    		fprintf(fpHTML,"<br><b>Label</b>: %s\n",(arList+a)->laLabel.cpLabel);
    		free((arList+a)->laLabel.cpLabel);
    		fprintf(fpHTML,"<br><b>Cost</b>: $%.2f\n",(arList+a)->laLabel.fCost);
    		fprintf(fpHTML,"<br><b>Biography</b>: %s\n<br>&nbsp;\n</body>\n</html>",(arList+a)->cpBio);
    		free((arList+a)->cpBio);
    		fclose(fpHTML);
    		fprintf(fpIndex,"  <li>\n  <p align=\"left\"><a href=\"%s\">%s %s</a></li>\n",cpFileName,(arList+a)->cpFirstName,(arList+a)->cpLastName);
    		free((arList+a)->cpFirstName);
    		free((arList+a)->cpLastName);
    		
    	}
    
    	free(arList);
    	fprintf(fpIndex,"</ul>\n<br>&nbsp;\n</body>\n</html>");
    	fclose(fpIndex);
    	free(cpFileName);
    
    }

  5. #5
    Code Goddess Prelude's Avatar
    Join Date
    Sep 2001
    Posts
    9,796
    >iDataRead = fscanf(fpDataFile,"%s %c %f", cpTemp,cTemp,fTemp);
    For future reference, the scanf family requires pointers be passed as arguments. Just the name is okay for arrays, but for regular variables you need to pass the address:
    Code:
    iDataRead = fscanf(fpDataFile,"%s %c %f", cpTemp,&cTemp,&fTemp);
    This was giving me an access violation and is probably what your problem is. Let me know if you have any more problems after changing your calls to scanf.

    -Prelude
    My best code is written with the delete key.

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