C/C++ :: File I/O - Reading Values From File
Jan 28, 2014
I am trying to write a program that will open a file with 2 points, take those points, determine what quadrant those points are in, and save the result back into the same file without truncating the data.
I'm having some trouble with my file I/O. I can't get my program to read the two values for X and Y that I put in the points.txt file. It simply uses whatever random number was used last time in that block of memory. In my points.txt file I put something like "4 -5" and it wont assign those numbers to my X and Y variables. I believe the issue is on line 25
#include <iostream>
#include <fstream>
using namespace std ;
int main() {
//defining X and Y
double X, Y ;
[Code] ....
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Jan 21, 2014
My problem is that I need to take a csv or excel file with tens of thousands of datapoints, write all points in a section of column to an array, perform calculations on them, and then write it back into another column.
I've been looking all over the internet for ways to do this easily. So far I have not found anything that I can follow and implement.Some codes have been slightly useful, but they aren't commented in a way I can understand. How to write code to take, for instance, lines from column b between 500-1000, write them to an array, and write another array 500 characters in column c. If that code could be commented, I have tried a few different techniques (counting commas), but haven't gotten anything to work.
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Oct 5, 2013
I have a .txt with a 0 or 1 to each line of the txt file. there are many values to read. I am reading the values and calculating how many each reoccur in a sequence (run-length encode). If i only use say 50 values coming in it works, but once i do the hundreds there are in the file it hangs. i am not sure why.
Code:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
FILE *infile;
FILE *outfile;
void PrintBinary(int x,int y);
[Code] ....
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May 20, 2013
We are supposed to split this lab into 3 files a .h and 2 .cpp's. The code I'll be talking about is going to be directed at the main.cpp file. Basically we are supposed to be able to enter as many classes into the program and when you are done the program is supposed to save the contents into a .dat file. This lab is working off of an older lab so I already have a .dat file I am trying to test with this program by reading it into my program when I first run it I prompt if the user wants to load previously entered courses and if they reply with a 'Y' the program will load the contents of the .dat file. Problem is right now when I load from the .dat file only the first class is correct. Every other class after that is just giberish. I've tried everything but can't get the restore part working. I also cannot get the save to .dat portion of this lab working either.Here is my code:
#include "Course.h"
#include <iostream>
using std::cout;
using std::cin;
using std::endl;
using std::ios;
[code]....
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Mar 25, 2013
I am trying to read an array values from Tmin.txt file. I take array size from user viz. number of raw & column and then, read the following data from Tmin.txt file which look like this:
20 40 20 25 30
20 30 40 20 25
20 40 20 25 30
20 30 40 20 25
30 40 40 30 40
I am using getline, and then converting it to int by using atoi. But my code is not working.
Code :
// reading a text file
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
[Code] ....
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Apr 12, 2014
My game is a sort of RPG with stats, money etc. I just recently added a save/load system using writing to a file. I initially got writing to a text file to work, then I got loading to work too.I eventually was able to read numbers from the file and assign them to integer variables in order.
My issue was I wanted to check if a save file existed, if it did, load it up, if it did not, go to character creation. I had a lot of trouble with this and after trying different code snippets to work I finally got it to check if a file existed, and execute the appropriate code.
My issue now is my code USED to go through each entry and assign variables in order.
Like the first number in the text file would be for the variable money, and it would read it, assign to to int money and scroll to down to the next variable for player strength, assign to to playerstr variable and so on. After making the tweak for loading it no longer functions like this, and makes the last entry in the text file the value for everything.
Here's my code:
Save Code:
{
ofstream savegame;
savegame.open("C:/Sounds/savegame.dat", ios::trunc);
savegame << money << endl;
savegame << playerstr <<endl;
[Code]....
I barely get how this code works, how can I tweak it to go through the file in order and assign variables one at a time?
At the current moment, it assigned the playerstr value to both money and playerstr int. But the save file being created lists the correct values in order.
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Dec 1, 2013
I am trying to read hex data from a file (not just hex values in text format). I was able to read it (02 EC) with "fread" into an char before but I need to change the Hex value into an integer in decimal.
I already read about strtol but I would prefer reading the hex Value into an integer.
Here is my code so far:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
int itrack1[1];
int itrack2[1];
[Code] ....
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Oct 11, 2013
I am trying to read the file which has the values stored in the following pattern
2 4 10 103 2 504 .... and so on
I Have opened the file and then passed the opened file to another function to process it further.
here is my code
#include <iostream>
#include <fstream>
#include <vector>
#include <stdlib.h>
[Code].....
now the problem is when the control exits the "while loop" in the function "readingValues(std::ifstream& myFile)it goes straight to catch block ?
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Dec 26, 2012
I have problem reading CSV file, i found many solutions but i still got one problem. I need to read CSV file and then these values show in List Control and here i have problem. Idk how to display it in List?
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Apr 4, 2014
I am attempting to read values from a file into a 2d array temp[31][2] (31 rows, 3 columns).I only want the values from the file to be read into the first two columns.I believe I am accomplishing that but when I go to print the array, I expect the first two columns to have the file data and the third column to have all zeros. The third column, however is printing such that the value is the next row/first column.
I'm not sure for instance why on the bottom loop for line 1 it doesn't print:
temp[0][0] temp[0][1] temp[0][2] 20 49 0 It instead prints: 20 49 1
Code:
#include <stdio.h> Code: #include <math.h>
FILE *inptr;
int main() {
int temp[31][2] = {0}, tempavg[31][2] = {0};
int i, j, k, sum;
inptr = fopen("ProgrammingProject14.txt", "r");
[code]....
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May 6, 2013
So I have this text file that I am trying to read from and store the values of each line in multiple variables.
Let's say my text file contains
AXSYZ3482 Tom 100 112
and my code below here works fine when the lines in the text file is separated by spaces.
while (fscanf(fp, "%s %s %d %d
", userID, name, &startLoc, &endLoc) != EOF) {
printf("%s %s %d %d
", userID, name, startLoc, endLoc);
}
But let's say my file was to look like this instead.
AXSYZ3482:Tom:100:112
But if i try this below...
while (fscanf(fp, "%s:%s:%d:%d
", userID, name, &startLoc, &endLoc) != EOF) {
printf("%s %s %d %d
", userID, name, startLoc, endLoc);
}
It seem to store the entire line in userID including the ":". I want to ignore the ":"'s and store everything in between in respective varibles in the order specified above.
So first string in userID, then ignore the :, then second string in name, and ignore the next :, and so forth. How I can accomplish this?
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Apr 12, 2015
Im trying to read from a file, line by line, with no specified number of values in the file. Check out my code:
int main() {
string x;
ifstream fin;
int count = 0;
char ch;
fin.open("CWC_Master.txt");
if(!fin)
[Code] .....
Now, this works great! However, its skipping some lines. And I dont know why. For example: Lets say that the input file is:
superman toy
sm2335
19.99
batman toy
bm5532
25.99
aquaman toy
am6786
26.00
Where it should output the above, instead it outputs every other one. Like:
superman toy
19.99
batman toy
25.99
aquaman toy
26.00
How can I fix my code so that it SIMPLY(i say simply because I am still a beginner coder) can read line by line?
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Nov 26, 2013
Program background: Ticket Sales Details You will sell tickets in advance and at the door. Prices for buying in advance and at the door will be given. Also, the total number of tickets sold in advance will be given. Each guest will have a unique number. If there are n tickets sold in advance, then these guests will be numbered 0 through n-1. As the event starts, requests to buy tickets at the door may be made and these guests will be numbered sequentially, starting at the lowest unassigned number. The maximum number of guests will be 1000. The first line of the file contains the following three values, separated by spaces: Cost of the presales tickets (in dollars), Cost of the tickets at the door (in dollars), and the number of presale tickets. The first two values will be positive real numbers to two decimal places and the last will be a positive integer.
The second line of the file will contain one positive integer representing the number of auction items followed by a positive real value to two decimal places (at most) representing the minimum bid increment, in dollars. The first value is guaranteed to be 1000 or less and the second will be in between 1 and 50, inclusive.
The third line of the file will contain all the prices of the auction items, in dollars, separated by spaces, in order. Thus, the first price is the price of item 0, the next price is the price of item 1, and so on. These values will be real numbers represented to up to 2 decimal places.
The fourth line of the file will contain the three following positive integers pertaining to the raffle: the number of raffle tickets available, the cost of a raffle ticket in dollars, and the number of raffle prizes. (It's strange to have raffle tickets that don't cost a whole number of dollars.)
The fifth line of the file will contain each of the values of the raffle items, in dollars, separated by spaces, in order. Thus, the first price is the price if item 0, the next price is the price of item 1, and so on. These values will be real numbers with upto 2 decimal places.
The sixth line of the file will contain ten positive integers representing the number of each of the drinks 0 through 9, in order, that are in stock.
The seventh line of the file will contain ten positive real numbers with upto 2 decimal places representing the price of each of the drinks 0 through 9, in order.
The eighth line of the file will contain a single positive integer, numEvents, representing the number of events that occur at the charity ball. These events are split into two groups: actions by guests at the ball and awards given (raffle, auction, person, totalrevenue). All of the actions precede all of the awards. You will produce exactly one line of output for each event described. Here are the formats of each event that could occur:
If a patron buys a ticket at the door, a command will be on a line by itself:
BUY TICKET k
where k is a positive integer indicating the number of tickets bought at the door. These guests will be numbered as previously mentioned. You are guaranteed that the total number of tickets bought, including presales, will not exceed 1000. This is what I have so far and I cannot figure out why it wont calculate the total revenue. I am not completely sure if it is even accessing the if statement in main.
Code:
#include <stdio.h> #include <stdlib.h>
#include <string.h>
#define N 1000
[Code].....
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Nov 7, 2014
I am reading a file then printing the data onto the other file. It is working, however when I check to see if each variable is being properly set after reading the file a issue arises.
Example of the file being read
Code:
Vehicle PV50CAN passed camera 1 at 05:33:26.
Vehicle W867BRO passed camera 1 at 05:33:29.
Vehicle KQ63ARU passed camera 1 at 05:33:38.
Vehicle K954ITQ passed camera 1 at 05:33:40.
Vehicle V220MXB passed camera 1 at 05:33:42.
[Code] .....
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Jan 5, 2014
If I am reading data from a .txt file with a person's last name and first name (e.g. Miller Andrew), How do I output the same data with the first name followed by the last ?(e.g. Andrew Miller) Do I use the ignore function?
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Aug 30, 2014
I want to know how to read a .pgm file from my hdd and store it in a 2d array so i can perform some action on the array later on. This is ny first time working with an imqge in c so i know nothing about it. .
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May 25, 2014
I have been given a task to make a c++ program that promptsd the user to enter a mp3 file name, read the ID3v1.1 tag and displays it. It then should prompt the user to to decide if they want to edit the comments section of it, then if they edit the section, it should re-print the updated ID3 tag. The list of genres are in a cstring that is as follows.
char genre[126][128] =
{
"Blues" "Classic Rock", "Country", "Dance", "Disco", "Funk",
"Grunge", "Hip-Hop", "Jazz", "Metal", "New Age", "Oldies", "Other",
"Pop", "R&B", "Rap", "Raggae", "Rock", "Techno", "Industrial",
"Alternative", "Ska", "Death Metal", "Pranks", "Soundtrack",
[Code] .....
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Aug 22, 2012
Using the feof() function in the output file i have the last value twice.
This is the input:
1 3 6
1 1 4
0 3 1
1 1 6
0 6 2
1 1 6
And the output should be:
12
6
15
13
But using the feof() the last value appears twice:
12
6
15
13
13
How can i change that?
while(!feof(pfile1)) {
sum=0;
fscanf(pfile1,"%d%d%d",&choice,&day,&val);
if(choice==0)
[Code] ....
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Apr 12, 2014
I'm a programmer on my high schools FIRST Robotics team. to give a bit of backstory if you don't know, we use C++ to program a 120 lb robot to compete in a competition released every year.
NOW - why I want to mess with an xml file. When we're messing with variable values to make sure everything moves at the right speed, stops at the right place, etc., we have to:
1. Change the file
2. Build code
3. Deploy code to the robot
4. Reboot the computer on the robot (FRC uses a 4 port cRIO by NI, takes ~ 50s to reboot)
5. Reconnect.
All in all, its about a 3-3.5 minute process to change values. Because of this, I would love to be able to store all my motor speeds, stopping positions, etc., in an xml file then simply ftp to the robot, mess with the xml, save it, and re-run the program.
SO! How would I even begin this process? I just want learning how to use one of those parsers like xerces to end up realizing that I can't use it in an application such as this.
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Apr 5, 2014
I am having problems writing this program for class the program must read a DAT file and print the Array and show the sums of A and B and the smallest and largest of the numbers in the DAT file
this is what it is suppose to look like after compiled
Array A[]: 60 40 80 100 30 20 90 50 10 70
Array B[]: 15 95 35 -10 45 -5 85 75 65 55 -20 25 5 25 -15
Sum of the elements of A[] = 550
Sum of the elements of B[] = 475
The smallest element of A[] = 10
The smallest element of B[] = -20
The largest element of A[] = 100
The largest element of B[] = 95
but this is what I get..
Array A[]: 60 40 80 100 301845634224184564560018456342248463648 1
Array B[]:3994112184685425110290441628889523994216 0 03994108399426418511697
04 -1184564557518455763132047600601153318
Sum of the elements A[] =1250410711
Sum of the elements B[] =-475173273
Smallest element of A[] =1845634224 at index 5
Smallest element of B[] = 0at index 5
Largest element of A[] = 1 at index 9
Largest element of B[] =1851169704at index 9
[code]....
P.S I have add the DAT file
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Apr 20, 2014
i've been trying to write array into file and read them into the same program again, but the output is all wrong.
Code:
#include<stdio.h>
int main()
{
FILE *fp;
char name[3][7];
int x;
}
[code]....
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Dec 9, 2014
How to read a grayscale jpeg image in C++ ?
How do I write the code to read the jpeg file and store its content in a 2D array
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Mar 29, 2014
I am practicing with C++ since I done most of C already and I have a problem with reading spaces from a .txt file.
I created a little program that creates a wannabe Cube in wannabe 3D xd, well to appear as 3D like:
Code:
cout << " O------O" << endl;
cout << " / /|" << endl;
cout << " / / |" << endl;
cout << " / / |" << endl;
[Code] .....
The actual code is a bit longer since it offers you to input the size and then it draws the pic. Now that wasn't so hard and I've done that but now I wanted to implement the "MessageBox" func for output.
I managed to write the cube in file cube.txt but when I'm reading from it 1 char at a time since I need to output as char array it avoids all spaces and new lines and just puts all symbols in the same row.
I didn't have that issue with C and I've found on stackoverlow a solution using strings & getline but I need it to be in "char" form.
How to actually read spaces and newlines? This is my current code for reading from file:
Code:
ifstream di("kocka.txt", ios_base::in);
char c[5000];
int br=0;
while( di >> c[br])
{
br++;
}
MessageBox(NULL, c, "Kocka", MB_ICONHAND);
di.close(); P.S kocka = cube (in croatian )
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Nov 3, 2014
I'm writing a program using Huffman algorithm to compress text file. I have tested my program by just printing the printing ASCII character to file and it worked fine. However, now I have to implement using bits and my program doesn't work. It seems like I'm not reading or writing the right bits. Here is the result of my testing:In the input file I put abc the input file to compress it. Then I uncompress it the out out is aaa. Below is a snippet of how I read and write bits
Code:
class BitInput {
istream& in; // the istream to delegate to
char buf; // the buffer of bits
int nbits; public:
BitInputStream(istream& s) : in(s), buf(0), bufi(8) { }
[Code] ....
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Dec 10, 2013
Basically I want to open a binary file containing utf-8 encoded characers. The length of the encoding is variable: 1, 2 or 3 bytes.
Rules are:
if the read byte has 0 as strong bit then it represents a single byte.
if the read byte has 11 as strong bits then it represents the first byte of a 2 or 3 length character.
if the read byte has 10 as strong bits then it represents the second or third byte of a 2 or 3 length character.
Each character encoded on 2 or 3 byte has to start with a 11xxxxxx and following bytes has to start with 10xxxxxx
So i need to go through his file, read byte per byte to analyse what kind of byte it is, sometimes go back to previous character etc etc
My goal is to identify all encoded characters in the file and then process them by convering them to Unicode value, storage in array etc...
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Feb 28, 2013
So im just trying to read in an pgm file and store it in an array,
Code:
int** imageArray;
//allocate the image array
imageArray = (int**) malloc(row * sizeof(int*));
for(i = 0; i < row; i++)
imageArray[i] = (int*) malloc(col * sizeof(int));
[Code]....
It stores about 1/3 of the file into the array, and then starts printing 6815940 6819608 followed by a bunch of 0's.
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