This is a homework problem for my C class. We are learning file I/O and I have successfully opened both files and now I have to use strtok() on the first file to extract number data and store it in a different file. I have successfully taken the numbers from the first line of the text file and stored them in the other file, but I can't get strtok() to run through the entire file. Any suggestions?
Not a whole lot...I'm drawing a blank here. I've tried to use " \n" so that the delimiter is both space and newline, but I don't think that it works...I thought that I could only have 1 delimiter anyway.
void main()
{
FILE *fp1 = NULL;
FILE *fp2 = NULL;
int i;
char strwarehouse[100];
char *token;
printf("Scanning files and parsing strings....\n");
fp1 = fopen("Assign9.txt", "r");
fp2 = fopen("numfile.txt", "w");
if (fp1 == NULL)
{
printf("ERROR OPENING FILE, TERMINATING PROGRAM\n");
}
else
{
fgets(strwarehouse, 100, fp1);
token = strtok(strwarehouse, " \n");
while (token != NULL)
{
if (isdigit(token[0]))
{
fprintf(fp2, "%s ", token);
}
token = strtok(NULL, " \n");
}
fclose(fp2);
fclose(fp1);
}
Related
void mergeFile(){
//allocate memory
char * firFile = (char*) malloc(MAX_SIZE);
char * secFile = (char*) malloc(MAX_SIZE);
char * conFile = (char*) malloc(MAX_SIZE);
char * buffer = (char*) malloc(MAX_SIZE);
char ch;
// get name of first file
printf("Enter name of first file: ");
__fpurge(stdin);
gets(buffer);
strcpy(firFile, FOLDER);
strcat(firFile, buffer);
//get name of second file
printf("Enter name of second file: ");
__fpurge(stdin);
gets(buffer);
strcpy(secFile, FOLDER);
strcat(secFile, buffer);
//get name of file will store
printf("Enter name of file which will store contents of two files : ");
__fpurge(stdin);
gets(buffer);
strcpy(conFile, FOLDER);
strcat(conFile, buffer);
//open 3 file with 'r' and 'w' mode
FILE * firPtr = fopen(firFile,"r");
FILE * secPtr = fopen(secFile, "r");
FILE * conPtr = fopen(conFile, "w");
//check 3 file NULL or not
if (firPtr == NULL) {
printf("Can not open %s file\n", firFile);
remove(conFile);
} else if (secPtr == NULL) {
printf("Can not open %s file\n", secFile);
remove(conFile);
} else if (conPtr == NULL){
printf("Can not open %s file\n",conFile);
}else{
// write all character in first file to file will store
// MAY NOT WORK
while ((ch = fgetc(firPtr)) != EOF)
fprintf(conPtr, "%c", ch);
// write all character in second file to file will store
// MAY NOT WORK
while ((ch = fgetc(secPtr)) != EOF)
fprintf(conPtr, "%c", ch);
printf("Two file were merged into %s file successfully\n!",conFile);
}
//clear all
free(buffer);
free(firFile);
free(secFile);
free(conFile);
fclose(firPtr);
fclose(secPtr);
fclose(conPtr);
}
I use fget to get character from file and write to another file, I work well when i use two file, one for read and one for store, But when i try to merge two file to another file, this code didn't work, no things in side contains file. I run this code in Netbeans 8.2, can you give me mistake from this code, thanks so much!
I'm trying to get two words in a string and I don't know how I can do it. I tried but if in a text file I have 'name Penny Marie' it gives me :name Penny. How can I get Penny Marie in s1? Thank you
#include <stdio.h>
#include <stdlib.h>
int main()
{
printf("Hello world!\n");
char s[50];
char s1[20];
FILE* fp = fopen("file.txt", "rt");
if (fp == NULL)
return 0;
fscanf(fp,"%s %s",s,s1);
{
printf("%s\n",s);
printf("%s",s1);
}
fclose(fp);
return 0;
}
Change the fscanf format, just tell it to not stop reading until new line:
fscanf(fp,"%s %[^\n]s",s,s1);
You shall use fgets.
Or you can try to do this :
fscanf(fp,"%s %s %s", s0, s, s1);
{
printf("%s\n",s);
printf("%s",s1);
}
and declare s0 as a void*
The other answers address adjustments to your fscanf call specific to your stated need. (Although fscanf() is not generally the best way to do what you are asking.) Your question is specific about getting 2 words, Penny & Marie, from a line in a file that contains: name Penny Marie. And as asked in comments, what if the file contains more than 1 line that needs to be parsed, or the name strings contain a variable number of names. Generally, the following functions and techniques are more suitable and are more commonly used to read content from a file and parse its content into strings:
fopen() and its arguments.
fgets()
strtok() (or strtok_r())
How to determine count of lines in a file (useful for creating an array of strings)
How to read lines of file into array of strings.
Deploying these techniques and functions can be adapted in many ways to parse content from files. To illustrate, a small example using these techniques is implemented below that will handle your stated needs, including multiple lines per file and variable numbers of names in each line.
Given File: names.txt in local directory:
name Penny Marie
name Jerry Smith
name Anthony James
name William Begoin
name Billy Jay Smith
name Jill Garner
name Cyndi Elm
name Bill Jones
name Ella Fitz Bella Jay
name Jerry
The following reads a file to characterize its contents in terms of number of lines, and longest line, creates an array of strings then populates each string in the array with names in the file, regardless the number of parts of the name.
int main(void)
{
// get count of lines in file:
int longest=0, i;
int count = count_of_lines(".\\names.txt", &longest);
// create array of strings with information from above
char names[count][longest+2]; // +2 - newline and NULL
char temp[longest+2];
char *tok;
FILE *fp = fopen(".\\names.txt", "r");
if(fp)
{
for(i=0;i<count;i++)
{
if(fgets(temp, longest+2, fp))// read next line
{
tok = strtok(temp, " \n"); // throw away "name" and space
if(tok)
{
tok = strtok(NULL, " \n");//capture first name of line.
if(tok)
{
strcpy(names[i], tok); // write first name element to string.
tok = strtok(NULL, " \n");
while(tok) // continue until all name elements in line are read
{ //concatenate remaining name elements
strcat(names[i], " ");// add space between name elements
strcat(names[i], tok);// next name element
tok = strtok(NULL, " \n");
}
}
}
}
}
}
return 0;
}
// returns count, and passes back longest
int count_of_lines(char *filename, int *longest)
{
int count = 0;
int len=0, lenKeep=0;
int c;
FILE *fp = fopen(filename, "r");
if(fp)
{
c = getc(fp);
while(c != EOF)
{
if(c != '\n')
{
len++;
}
else
{
lenKeep = (len < lenKeep) ? lenKeep : len;
len = 0;
count++;
}
c = getc(fp);
}
fclose(fp);
*longest = lenKeep;
}
return count;
}
Change your fscanf line to fscanf(fp, "%s %s %s", s, s1, s2).
Then you can printf your s1 and s2 variables to get "Penny" and "Marie".
Try the function fgets
fp = fopen("file.txt" , "r");
if(fp == NULL) {
perror("Error opening file");
return(-1);
}
if( fgets (str, 60, fp)!=NULL ) {
/* writing content to stdout */
puts(str);
}
fclose(fp);
In the above piece of code it will write out the content with the maximum of 60 characters. You can make that part dynamic with str(len) if I'm not mistaken.
I want to check if there are any duplicates in a .txt file. I've wrote a code but it's not running. I'm not sure about opening the norep.txt file in "a+" mode. The idea is to put the first word of my text in the norep.txt file, then compare every word in the text.txt with the words in norep.txt and copy only the words I need in the file.
#include <stdio.h>
#include <stdlib.h>
int main() {
FILE *fd;
FILE *ft;
char aux[30];
char aux1[30];
int len;
fd = fopen("c:\\text.txt", "r");
if (fd == NULL) {
puts("Error");
}
ft = fopen("c:\\norep.txt", "a+");
if (ft == NULL) {
puts("Error");
}
fscanf(fd, "%s", aux);
fprintf(ft, "%s", aux);
rewind(fd);
rewind(ft);
while (!feof(fd)) {
fscanf(fd, "%s", aux);
while (!feof(ft)) {
fscanf(ft, "%s", aux1);
len = strcmp(aux, aux1);
if (len != 0) {
fprintf(ft, "%s", aux);
}
}
rewind(ft);
}
return 0;
}
You should flush the output file before you rewind it.
fflush - flush a stream or fflush
Of course, this will not fix your problem because:
Note below that the manual says that reposition operations are ignored so that your attempt to read will always find the end of file.
append: Open file for output at the end of a file. Output operations
always write data at the end of the file, expanding it. Repositioning
operations (fseek, fsetpos, rewind) are ignored. The file is created
if it does not exist.
What you should probably do is create an internal memory table that keeps all the unique entries and write it out to a new file after all processing is done. As you read the fd file, check the list and add a new entry if it is not already in the list. Then after you have finished processing fd, then and only then write out your list. Of course, this may be too big depending on the size of your data file.
You could append each unique entry to the output file as you go. but you would need to have some method of checking the previous entries without trying to read the output file.
The usual way to go about this is to read the input file word for word, store the necessary information in some way and then, after you have read all information from the file, write the desired output to the output file.
A rough skeleton of that approach might look like this:
int main()
{
const char *infile = "text.txt";
const char *outfile = "norep.txt";
FILE *in;
FILE *out;
char word[30];
// (1) Read all words
in = fopen(infile, "r"); // .. and enforce success
while (fscanf(in, "%29s", word) == 1) {
// store word somewhere
}
fclose(in);
// (2) Determine unique words somehow
// (3) Write out unique words
out = fopen(outfile, "w"); // .. and enforce success
for (i = 0; i < nunique; i++) {
fprintf(out, "%s\n", unique[i]);
}
fclose(out);
return 0;
}
The actual algorithm to fin the unique words is missing from this incomplete skeleton code.
If you really want to test the words in a file for uniqueness without using additional memory beyond the current word, you can open the input file twice, with independent file pointers. Then you can write a loop like so:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
int main()
{
const char *infile = "text.txt";
const char *outfile = "norep.txt";
FILE *in1;
FILE *in2;
FILE *out;
char word1[30];
char word2[30];
in1 = fopen(infile, "r");
in2 = fopen(infile, "r");
out = fopen(outfile, "w");
if (in1 == NULL || in2 == NULL || out == NULL) {
fprintf(stderr, "Could not open all required files.\n");
exit(1);
}
while (fscanf(in1, "%29s", word1) == 1) {
int count = 0;
while (fscanf(in2, "%29s", word2) == 1) {
if (strcmp(word1, word2) == 0) count++;
if (count > 1) break;
}
if (count == 1) fprintf(out, "%s\n", word1);
rewind(in2);
}
fclose(in1);
fclose(in2);
fclose(out);
return 0;
}
This will, of course, re-read the file as often as there are words in the file. Not a good approach to find the unique words in Moby-Dick. I recommend that you look into the memory-based approach.
First off I am creating a program that will read lines of characters and find words (they don't have to have meaning, i.e 'ab' could be word ) and storing them in the appropriate data structure. I used trie structure to store the words. I am given a mapping file as a command line argument yet inside the mapping file I have two data files I need to gain information from. The usage interface is as follows: first(program name) <mappingfile>.
Inside the mapping file, there exists two data files: <dictFile> and <dataFile>. Im not sure how to read and store the information presented the two data files. So far I have the following:
#include <stdio.h>
#include<stdlib.h>
void readDict(FILE *dict_file){
}
int main(int argc, char *argv[]){
FILE* file;
if(argc != 2){ //error in inputing, not 2 files
printf("error\n");
return 0;
}
file = fopen(argv[1],"r" ); //reading the mapping file
input;
if(file == NULL){ //nothing inside file
printf("file does not exist\n");
return 0;
}
}
My goal is to have pointers point to respective data files in the mapping file which I can use for reading their contents.
I will be given the following input in the command line:
first(program name) <mappingfile>.
Inisde the mapping file contains the lines of two plain .txt files in the form
<dictFile> <dataFile>.
I wish to access both contents of <dictFile> and <dataFile>.. with pointers to the respective file.
If I understand your question correctly you want to parse a file where each line contains the filenames of two other files and then read from these. What you can do is use fgets to read your mapping file line by line. What you can do next is use the function strtok to split your string on a whitespace. I'll break it down for you step by step.
Firstly we want to open the mapping file for reading
if((file = fopen(argv[1],"r")) == NULL) {
perror("error opening file");
return 1;
}
This will try to open the mapping file specified by the command line arguments of your program and if it fails it will print a corresponding error message.
while(fgets(buf, sizeof(buf), file) != NULL) {
After we've opened the file we want to iterate through all the lines until we reach the end of the file and fgets will return NULL. fgets will put the current line into buf.
dictfilename = strtok(buf, " ");
datafilename = strtok(NULL, " ");
strtok(dictfilename, "\n"); /* Remove any trailing newlines */
strtok(datafilename, "\n");
We need to split the line read by fgets by a delimter (a whitespace) so we know which part corresponds to the dictfile and the datafile. This is done by using the strtok function which returns a pointer to the substring before the whitespace and when passing in NULL it will return a pointer to the substring after the whitespace. A slightly weird way of removing any trailing newlines is to use strtok and the newline as a delimiter.
if((dictfile = fopen(dictfilename,"r")) == NULL) {
fprintf(stderr, "error opening file %s: %s\n", dictfilename, strerror(errno));
return 1;
}
if((datafile = fopen(datafilename,"r")) == NULL) {
fprintf(stderr, "error opening file %s: %s\n", datafilename, strerror(errno));
return 1;
}
Very similiarly to how we open the mapping file, we now open the two files found on the current line read by fgets with "r" mode which opens for reading. If the file does not exist or cannot be found, the fopen call fails.
printf("Content of %s:\n", dictfilename);
while ((c = getc(dictfile)) != EOF)
putchar(c);
printf("\nContent of %s:\n", datafilename);
while ((c = getc(datafile)) != EOF)
putchar(c);
This is a very simple method of "dumping" the content of the files. It uses getc to read the next char from the file and prints it until it reads EOF. This is where you should do your own function.
fclose(dictfile);
fclose(datafile);
And don't forget to close the files afterwards or you will leak resources.
Finally here is the code on what I just described
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#define MAX_LENGTH 100 // change this to the actual maximum length of your lines.
int main(int argc, char **argv){
FILE* file, *dictfile, *datafile;
char c;
char buf[MAX_LENGTH];
char *dictfilename, *datafilename;
if(argc != 2) {
fprintf(stderr, "Usage: %s <mapping file>\n", argv[0]);
return 0;
}
if((file = fopen(argv[1],"r")) == NULL) {
perror("error opening file");
return 1;
}
while(fgets(buf, sizeof(buf), file) != NULL) {
dictfilename = strtok(buf, " ");
datafilename = strtok(NULL, " ");
strtok(dictfilename, "\n"); /* Remove any trailing newlines */
strtok(datafilename, "\n");
if((dictfile = fopen(dictfilename,"r")) == NULL) {
fprintf(stderr, "error opening file %s: %s\n", dictfilename, strerror(errno));
return 1;
}
if((datafile = fopen(datafilename,"r")) == NULL) {
fprintf(stderr, "error opening file %s: %s\n", datafilename, strerror(errno));
return 1;
}
// do something with the files (e.g read all the content)
printf("Content of %s:\n", dictfilename);
while ((c = getc(dictfile)) != EOF)
putchar(c);
printf("\nContent of %s:\n", datafilename);
while ((c = getc(datafile)) != EOF)
putchar(c);
printf("\n");
// don't forget to close the files when you're done with them.
fclose(dictfile);
fclose(datafile);
}
fclose(file);
}
If I understand you correctly this should do it. Note that it assumes your filenames don't have any spaces. And if you want to use the "non secure" api's you need to add _CRT_SECURE_NO_WARNINGS to the project properties under Configuration Properties -> C/C++ -> Preprocessor -> Preprocessor Definitions.
#include <stdio.h>
#include<stdlib.h>
void readDict(FILE *dict_file){
}
int main(int argc, char *argv[]){
FILE* file;
if(argc != 2){ //error in inputing, not 2 files
printf("error\n");
return 1;
}
file = fopen(argv[1],"r" ); //reading the mapping file
//input;
if(file == NULL){ //nothing inside file
printf("file does not exist\n");
return 1;
}
char dictFileString[256], dataFileString[256];
fscanf( file, "%255s %255s", dictFileString, dataFileString );
FILE *dictFile, *dataFile;
dictFile = fopen( dictFileString, "r" );
if (dictFile == NULL) {
printf( "%s does not exist\n", dictFileString );
fclose(file);
return 1;
}
dataFile = fopen( dataFileString, "r" );
if (dataFile == NULL) {
printf( "%s does not exist\n", dataFileString );
fclose(file);
fclose(dictFile);
return 1;
}
readDict(dictFile);
// The additional logic would be placed here.
fclose( dictFile );
fclose( dataFile );
// If you need to read additional file names then loop
// back up to read the next line of 'file'
fclose( file );
return 0;
}
I am having problems with copying txt files. I need to info from one file to another.
My code looks like this,
_tprintf (TEXT("%s\n"), FindFileData.cFileName);
memset(fileName, 0x00, sizeof(fileName));
_stprintf(fileName, TEXT("%s\\%s"), path, FindFileData.cFileName); //iegust
FILE *fptr = fopen(fileName, "r");//atver
fscanf(fptr,"%[^\n]",c); //iegust datus no faila
printf("Data from file:\n%s",a);
strcpy(a, c); //nokope datus
buffer2 = strtok (c, ","); //norada partraukumu un tadas lietas
while (buffer2) {
buffer2 = strtok (NULL, ",");
if(i<1){ printf("%s\n", c);}
i++;
while (buffer2 && *buffer2 == '\040'){
buffer2++;
// TODO ieliec iekavinas
}
}
And after that I use basic fputs().
My problem is that this code ignores new lines. It prints out fine, each string in it's own line, but that does not happen in file. (\n).
Your problem is that you just need to copy information from one file to another. So, why you don't use a simple solution to do it than your. I have a snipet code can solve your problem easily as shown below.
If I am wrong about your question, please give me advices.
#include <stdio.h>
#include <stdlib.h> // For exit()
int main()
{
FILE *fptr1, *fptr2;
char filename[100], c;
printf("Enter the filename to open for reading \n");
scanf("%s", filename);
// Open one file for reading
fptr1 = fopen(filename, "r");
if (fptr1 == NULL)
{
printf("Cannot open file %s \n", filename);
exit(0);
}
printf("Enter the filename to open for writing \n");
scanf("%s", filename);
// Open another file for writing
fptr2 = fopen(filename, "w");
if (fptr2 == NULL)
{
printf("Cannot open file %s \n", filename);
exit(0);
}
// Read contents from file
c = fgetc(fptr1);
while (c != EOF)
{
fputc(c, fptr2);
c = fgetc(fptr1);
}
printf("\nContents copied to %s", filename);
fclose(fptr1);
fclose(fptr2);
return 0;
}