C :: Assigning Line Of File To String

Mar 28, 2014

I'm making a game that requires the user to enter a correct username and password to play. I have a list of accepted ones saved in a txt file. How do i read each line of the file and check it with the one entered? I know how to use strcmp(string1, string2). I just need to know how to move from one line to the next. This is what I have for this part of the program so far. Also, I think im using the feof() wrong.

Code:
id = fopen("F://CS223/namepass.txt", "r");
score = fopen("F://CS223/scores.txt", "a");
srand(time(NULL));
if(id == NULL)
{
printf("ERROR");

[Code] .....

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C++ :: Read Line By Line From Text File To String

Jul 5, 2013

I have a text file (test.txt) with the following data:

01,05,25,20130728
01,06,25,20130728
01,07,25,20130728
01,08,25,20130728
01,05,25,20130728
01,05,25,20130728
01,05,45,20130728
01,05,65,20130728
01,05,85,20130728
01,05,35,20130728
01,05,25,20130728
01,05,35,20130728

I want to read this to one string called line. So far I have this code:

string line;
ifstream myfile ("/home/Test.txt");
if (myfile.is_open()) {
while (myfile.good()) {
getline (myfile, line);
for (int a = 0; a <= 335; a++) {
cout <<line.at(a);
} }
myfile.close();
}

so far its only printing the first line and then throwing an instance of 'std::out_of_range'

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C++ :: String Operation While Reading Line By Line From A File

May 12, 2014

I have to read the information about logic gates from a file. The file format is shown below:

Code:
gateOne = NAND(inpA, inpB)
gate2=NAND(1,2)
3 = NAND(23,25,26)

As, it can be seen from the above structure that whitespaces are not same everytime. So, to deal with this situation, i am using boost library to remove all whitespaces from the line which is being read and then try to find the name of gate and its input. My code is given below which is able to correctly find the gate names and its first input...but my code is not able to find the second, third and so on input names.

Code:
//C
#include <stdio.h>
//C++
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <cstring>
#include <boost/algorithm/string/erase.hpp>

[Code] ....

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C++ :: How To Display A String Per Line On TXT File

Mar 6, 2015

How can i display a string per line on the .txt i made? There are 2 .txt files, the one has: John Finn Xach The other is: password1 password2 password3 Question is: How can i display, let's say, i input "John" so it will display something like this "John's password is password1" or if i input Xach, "Xach's password is password3" When i use something like :

Code:

while(getline(passwordFile, str))
{cout<< username <<" password is " << str;
break;
}

It will work for when i input "John", but it doesn't work if I input "Finn" or "Xach"

EDIT: I tried this one:

Code:

while(getline(userFile, str1) && (passwordFile, str2))
{
cout<< str1 <<" password is " << str2;
break;

The output would be: Finn password is password1

It iterates the username but not the password.

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C :: How Can A Multi-line String Be Read Line By Line

Mar 7, 2014

How can a mulitline string be read line by line

ex: str = "PERIOD="week"
DAY="day"
TIME="time"";

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C :: Command Line And Converts String From File Into A Linked List

Jul 10, 2013

My program takes in an input file from the command line and converts the string from the file into a linked list and then depending on the command it will manipulate the string to either reverse the list, print the list, or take a character out...I'm having trouble taking a character out, my code compiles fine but doesn't change the string at all

Code:

#include <stdio.h>
#include <stdlib.h>
#define SIZE 1024

[Code]....

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C++ :: Assigning String Tokens To Array?

Oct 20, 2014

I need to dynamically build a control file for a SQL loader but when tokenizing line values read from a file i am unable to work/assign the last value to a variable even though i can print the actual token value while in the loop.

Below is the code snippet i have and get:

Code:
//headElement declared as headElement[42]
//getCol function is used to decode column keys present in line being read
istringstream ss(line);

[Code] .....

I've attached a sample file as well.

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C :: Assigning String To Array And Compare It?

Mar 20, 2013

I have this code :

#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

[Code] ...

And this error occued with me I don't know why ???

myHeader.h:42:19: error: expected ")" before string constant

This code is compiled from file called myHeader.h ...

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C :: Assigning A Pointer To A String Literal

Sep 13, 2013

In another forum, this example code fragment was stated as being an example of undefined behavior. My understanding is that a literal string exists from program start to program termination, so I don't see the issue, even though the literal string is probably in a different part of memory.

Code: /* ... */
const char *pstr = "example";
/* or even */
char *pstr = "example";
/* as long as no attempt is made to modify the data pointed to by pstr, */
/* unless pstr is later changed to point to a stack or heap based string */

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C++ :: Assigning String Tokens To Array?

Oct 20, 2014

I need to dynamically build a control file for a SQL loader but when tokenizing line values read from a file i am unable to work/assign the last value to a variable even though i can print the actual token value while in the loop.

Below is the code:

//headElement declared as headElement[42]
//getCol function is used to decode column keys present in line being read
istringstream ss(line);
wfile << "LOAD DATA " << endl <<
"INFILE * " << endl <<

[code]....

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C :: Reading A File Line By Line (invalid Write Of Size X)

Aug 17, 2014

I am trying to read a file line by line and then do something with the informations, so my method looks like this:

Code:
void open_file(char *link) {
FILE *file = fopen(link, "r");
if (file == NULL) {
fprintf(stderr, "Could not open file.
");
exit(EXIT_FAILURE);

[Code] ....

1) The first complain of valgrind is at the line where I use fgets and its telling me (invalid write of size x), but I have allocated my line to 56000 and the read line is shorter, why is there a write size error then :S?

2) at the line where I realloc where I try to shrink the space he's telling me: Address .... is 0 bytes inside a block of size 56000, But I know i need only this space so why is there a write over space error :S??

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C :: Reading A File Line By Line And Storing It Backwards Into A List

Sep 25, 2013

So I'm reading a file line by line and storing it backwards into a list. So if the file has has this format...
1
2
3
4

The code should store each line in a list as such...
4, 3, 2 ,1

Instead the code will store the last variable in all nodes. So the final list will look like this...
4, 4, 4, 4

Here is my code...

struct node *head = NULL;
int i;
while(read(in, &i, sizeof(int)) != 0) {
struct node *temp = malloc(sizeof(*temp));
temp->line = &i;
temp->next = head;
head = temp;
}

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C :: Copying File Line By Line Using Dynamic Memory Allocation

Jul 15, 2013

I need to read lines from one file and copy them line by line into another file using dynamic memory allocation. It compiles but gives me a seg fault. Why/How?

Code:
int main(){
FILE *fp1;
FILE *fp2;
FILE *i;
fp1=fopen("file1","r");
fp2=fopen("file3","w+");

[Code] ....

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C++ :: Read Txt File Line By Line Write To Vector

Oct 5, 2013

I need to read a text file which has various lines containing integers. I need to write those integers separately in a vector. Example, the first line of the text file contains 3 9 8 7 6 so vector[4]=3, vector[3]=9, vector[2]=8 and so on. Next read the second line 4 1 2 3 4 5 and write to another vector vector[5]=4, vector[4]=1...

I tried the code below but it will write from the second line, the whole line in one vector index.

int str; // Temp string to
cout << "Read from a file!" << endl;
ifstream fin("functions.txt"); // Open it up!
string line;
// read line count from file; assuming it's the first line
getline( fin, line );

[Code]...

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C/C++ :: Reading From A File Line By Line With No Specified Number Of Values

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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C/C++ :: How To Get Last Line 10 Char In Text File If Last Line Is Null

Aug 24, 2013

I can able to get the last line ten chars but i cant get if the last line is null.

here is my code

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
using namespace std;
int main(int argc, char *argv[]) {

[Code] ....

here with i have enclosed my file where i am pick my last ten chars ...

Attached Files : log.txt (4.8 KB)

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C :: Reading File Line By Line On Windows?

Oct 13, 2014

How to read a file line by line and then later access them by doing something like

Code:
lines[0] //Line number one
...
lines[100] //Line number one hundred and one
lines[100][0] //L
lines[100][1] //i
lines[100][2] //n
lines[100][3] //e
lines[100][4] //
lines[100][5] //n
...

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C++ :: How To Read Data From A File Line By Line

Jul 2, 2013

I have an external file with one column of data. If I have a counter value let say counter =1, and counter++ and so on. How I can write such a c++ code that if the value of counter and value from the external file are same then generate an action let say cout both values i.e. value of counter and value from external file.

for more information, here is an example:

data in file(in one column): 2 6 8 9 10...
value of counter : 1 2 3 4 5 6 7 8 9...

then cout values only if value of counter and value from the file is same.

Here is my code so far, but it does not seem to work;

#include<iostream>
#include<fstream>
using namespace std;
int main() {
const int SIZE = 10; //Size declaration of array
int hours[SIZE]; //Array declaration

[Code]...

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C++ :: Read File Content Line By Line

Jan 23, 2015

I am reading my file (20GB) line by line using boost like this

PHP Code:

boost::interprocess::file_mapping* fm = new boost::interprocess::file_mapping("E:Mountain.7z", boost::interprocess::read_only);
boost::interprocess::mapped_region* mr = new boost::interprocess::mapped_region(*fm, boost::interprocess::read_only);

 char* bytes = static_cast<char*>(mr->get_address()); 

An exception is thrown in the second line while allocating memory for mr.

I use boost because it can also work in Mac which my code will be ported to.

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C :: Scanning CSV File And Assigning Variable To It

Dec 26, 2013

How to scan a CSV file and assigned variable to each of the integer scanned in a csv file

an example of the csv file:
0001,40,,10

How do I scan the CSV file and assign 0001 to variable student id, the 40 to variable module 01,the 1 without input entered to module02 and 10 to module03

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C++ :: Reading From File Line By Line?

Jul 27, 2013

First of all I need to know how to read from file.

Second, I need to read line by line from the file.

For example, the file contains:

8H 3S TH 9D 5S
5D KD 9H 4D 3D
8C TD 5D QS 2C

I wanna use array, so I need to store 8H in array[0], 3S in array[1], until 5S get stored in array[4].

I need to read the first line, the the second, and then the third.

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C :: Reading Values From File To First 2 Columns Of 2D Array / Assigning 0 To 3rd Column

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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C++ :: Write A Loop Assigning Variable X To All Positions Of String Variable

Sep 8, 2013

I have to write a loop assigning a variable x to all positions of a string variable and I'm stuck. I don't have extensive experience with arrays and I'm also a bit confused about C-String. The problem is below.

"Given the following declaration and initialization of the string variable, write a loop to assign 'X' to all positions of this string variable, keeping the length the same.

char our_string[15] = "Hi there!";

(Please note this is a 'C-string', not C++ standard string.)"

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C++ :: How To Take Multiple Line String

Feb 3, 2013

I want to take multiple line string in c++. How can I take this.

Such as I want to take this as input:

HELLO MY LOVE, I M HAPPY BECAUSE SOON I WILL BE TO YOUR SIDE.
THIS TIME WITHOUT YOU HAS BEEN ETERNAL.
I INVITE YOU TO THE ZOO ONE TO SEE THE ZEBRAS AND GORILAS.

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C++ :: Reading TXT Line Into A String?

Sep 11, 2014

void login() {
//username, password, option to register, option to exit, link to website
cout << "Would you like to login(1), or press anything else to register.?" << endl;
cin >> loginYorN;
if (loginYorN == 1) {
cout << "Please enter your username: ";
cin >> accountInfo[1];

[code]...

So as above, I ask them to input 1 for login, anything else for register. Whatever they input, it get's stored into loginYorN, then I check to see what they input. If they put '1' for input, then I ask them for their username, store that into accountInfo[1], and then asking for the password, storing that into accountInfo[2].

Now here is where I need to input line 1(username) from login.csv or login.txt and line2(password) and storage these into accountID and accountPW.

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C++ :: How To Put End Of String Mark At The End Of Each Line In Array

Oct 28, 2014

Basically I am writing a program that will ask the user to input some names and then I will sort the names. However, right now when I input the characters, it prints out everything, including the empty spaces. How do I put an end of string mark at the end of the line, when the user hits enter

void main() {
constintMaxNames(20);
constintMaxLetters(15);
charNames[MaxNames + 1] [MaxLetters + 1];
intNumRows;

[Code] .....

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