C :: Read From Stdin (File) Character By Character
Nov 10, 2013
I have to optimize a code for below scenario. I am reading stdin (a file redirected to stdin) character by character. How many chars are going to come is not known. After every few chars there is a seaparator. e.g $ as below
rhhrkkj$hghjhdf$ddfkrjt
While reading, if the separator arrives I'm processing the string stored before that separator and then continue reading stdin in same fashion, till EOF. I am using getc(stdin) to read chars.
Using gprof I can see most of the program time is spent inside main() , for this reading logic. Rest of the program is just some insert and search operations. I am getting time of 0.01 secs at the moment, want to reduce further.
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Aug 10, 2012
How do I write an a program that will read an input file character by character?
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Oct 6, 2013
In my program, I'm supposed to read a text file (the name of which is given to me as a command line paramater, as long with an integer), and display the text in a specific format (each line can only be as long as the integer). However, I'm having trouble even reading the text file. I don't know the syntax. I'm only allowed to edit the function that does the formatting, and the code in that is
void typeset (int maxWidth, istream& documentIn)
I don't know how to 'read' the file, as most examples online are ifstream, or openFile or something like that. What I want to do is just read the first character of the file, and continuously keep reading characters until the end of the file.
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Jul 25, 2012
Double values are stored in text file. 23.5 36.8 34.2 ... My teacher told me to read them character by character and then make words, like i have to read "2" "3" "." "5" and now have to make it or treat it as word and then using atoi(). I have to convert it into double. but i dont know how to do this....
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Sep 25, 2012
I am working to make a translating software from an Urdu sentence into Hindi and vice versa, i am using visual c++ 2010 software with c++ language. i have written an Urdu sentence in a text file. now i want to get a single character one by one from that file so that i can work on it to convert it into its equivalent Hindi character. when i use get() function to get a single character from input file and write this single character on output file, i get some unknown ugly looking character placed in output file. My code is as follows
Code:
#include<iostream>
#include<fstream>
#include<cwchar>
#include<cstdlib>
using namespace std;
void main() {
wchar_t arry[50];
[Code] .....
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Sep 14, 2014
I keep getting this warning message and I do not know how to fix it. Is it because I'm using char to instead of strings to replace all 't' with 'lp'?
#include<iostream>
#include<string>
#include <stdio.h>
using namespace std;
char * scanf(char * a) {
[code]....
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Sep 13, 2014
So I'm trying to create a function that replaces any instance of a character in a string with another. So first I tried the replace() string member function:
In my implementation file
void NewString::ReplaceChar(const char& target,const char& entry)
{
this->replace(this->begin(),this->end(), target, entry);
};
Main program
#include "NewString.h"
using namespace ...;
int main()
[Code].....
Instead of replacing the the l's with y's it outputted a long string of y's. Also, NewString is derived from the string class (it's for the assignment). the header and whole implementation file, already tested.
I've also tried, instead, to use a for loop in ReplaceChar() but I need to overload the == operator and I don't know how I should exactly:
bool NewString::operator ==(const char& target)const {
if(*this == target)
return true;
[Code]....
I want the == operator to test if the value in the char array is equal to target but I'm not sure how to pass in the position. I'm guessing the this pointer in ReplaceChar() is not the same as the one dereferenced in ==() because target is never replaced by entry in the string.
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Feb 13, 2014
how to carry out the conversions. The assignment is the normal hex to octal and Quart (base 4) via bit munipulation which I have worked out myself. However, I have been trying all day to figure out how to read in a string such as H1234, or O4567. How to parse the input I can handle the remainder myself. I'm just stuck and I've tried for hours.
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Mar 11, 2012
Below given is the code, which allocates memory for a structure dynamically and stores value in its member. The problem is in the last scanf statement which reads 'ch'. The code will be in infinite loop as it doesnt executes the last scanf statement. The solution for this is (i use this) to add one more similar scanf statement for 'ch' in the very next line. If i do so, it executes the statement, reads 'ch' and then continues.
I want to know why it behaves like that..
struct student{
int usn;
};
int main(){
char ch;
struct student *s;
s=(struct student *)malloc(sizeof(struct student));
[Code] ....
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Nov 1, 2013
So running the following code
Code:
#include <stdio.h>
int main(void) {
char c;
int i=1;
while (scanf("%c", &c)==1)
printf("loop sequence %i: %c(%i)
[Code] ......
Done it seems a "carriage return" serves two purposes here, one is to signal the program to read in the character typed in before the "carriage return", another serves as a second character typed, how can i do this cleanly, that is without having to use a "carriage return" as the second character to signal "I've typed in the first character already".
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Jan 10, 2014
How to do this?
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Jan 12, 2015
I'm very new to c programming and I have some background in C# and java. I am supposed to read a string from input then determine in that string, which character is the largest, i.e. I think b>e and e>z, e.t.c. If the string is empty I should return ' '.
I haven't done any programming in C before and I don't know how to handle strings and characters in C.
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Sep 10, 2013
I'm trying to get the hang of the declaration and use of char. I'm trying to write a program that reads sentences from the user and changes them based on their character choices, I keep getting load of compiler errors.......am I off to a good start or am I way off?
#include<iostream>
#include<string>
#include<cstring>
#include<cctype>
using namespace std;
int main() {
char *quit*;
char sentance [100];
[Code] ....
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Jul 4, 2014
Can we do this :
Code:
char strings[][100]={"ABC","EFG","IJK","LKM"};
char temp[100];
temp=strings[1];
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Jul 5, 2013
I'd like to remove the character % from a text file using c++
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May 26, 2012
How can I count the occurrences of each character in a text file and then organize them by most occurring?
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Nov 24, 2013
I have this code for a computer project... (store management) but the character strings are not copied on text file..
#include<iostream.h>
#include<conio.h>
#include<fstream.h>
class Store {
public:
char *item_name[5];
store()
[Code] .....
Now when i run the program, it gives a error :::
ERROR
address 0x0
How can i write these strings to the text file?
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Feb 12, 2013
I'm writing a program that stores records into a file and then these records can be printed out. A last name, first name, and score is stored to be exactly 36 characters long (using leading spaces to pad) making it easier to retrieve specific records. For example, three records stored in the file would like like this: (the underscores are simply to illustrate the distance, they are not in the file itself)
_______lastname_______firstname__90__________lname __________fname_100___________last___________first __60
When printed out, the names are formatted as follows:
lastname, firstname: 90
lname, fname: 100
last, first: 60
However, when I print them out this is what I get:
lastname, firstname: 90
lname, fname: 100$
last, first: 60H
For some reason, for any record after the first, an extra character is added to the end. These characters are not in the file, so I was thinking that the array for some reason wasn't being filled completely, (the array is initialized to size 36 and 36 characters are read from the file using fread) so it was printing out a random character assigned to the 36th array position. Except the character never changes, (always a $ for record 2, H for record 3, l for record 4 if i remember) and I've tried reducing the array size or the number of character read and it's the string that gets altered, the random character always remains. I figure the problem must be in the print_records function (appending seems to work no problem). Anyway here is my print records and appending records code.
Code: /*
- Prints a single record stored in the file pointed to by ifp.
*/
void print_record(FILE *ifp, int record) {
[Code]......
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Jan 7, 2015
I'm facing a problem regarding data entry in file.I'm making arrays which terminates when I press enter key but problem is that character at 0 index is not in file while rest of the indexes are there .. In other words,while writing on file my first character of any array got missed and did'nt present in the file ..
char CNIC[10000];
std::fstream file1;
cout<<"Enter CNIC's >>>>>>>>>>> "<<endl;
file1.open("Nadra database.txt",std::fstream::in | std::fstream::out | std::fstream::app);
if(!file1) {
cout<<"File was not open";
} else {
for(int i=0;i<11;i++)
[code]....
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Apr 26, 2014
I'm trying append more characters to a txt file after write title of foreground window and a newline character, but after first character, the next appear after a newline. Here is result => [URL].... and here is my code:
I'm using Dev C++ 4.9.9.2 compiler.
Code:
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
using namespace std;
LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam);
[Code]....
I have made some changes for this =>
Code:
if (str_window)
strcpy(str_window,str_window);
strcat(str_window,"
");
log(str_window);
[Code]...
Now print only first character in digitation after title of active window. Still printing wrong see => [URL]..... Word "good" as sample.
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Jan 27, 2014
I'm trying to read a file that is in byte format then append it onto another file. I'm doing this with unsigned char variable types because they're always one byte. Since the format is simply using bytes, they don't care about the character representation. However, when I read the characters in then put them out again, the '/n' character is always preceded by the '/r' character. In hexadecimal this looks like 0D0A. I have no control of this, and it seems as if it's being done automatically by the ofstream.put() function.
So, is there a way to take away this appending of characters and simply writing the raw data to the file?
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Apr 19, 2014
all i want to do is to read a fixed char array sized 4 from user and pass it to Binary File then Print Encrypted content from the the File to the console screen .. but it seems it prints the same input every time .. and i tried everything .. it works fine with integers and strings .. but when it come to char array nothing ..
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
[Code].....
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Jan 2, 2014
I am trying to store a large text file into an array so I can count the number of characters.
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Oct 31, 2014
How do I output a Unicode number if I extract a character off a console or out of a file.
If I do the below, I use the Unicode number to show a character. The below shows me 25² .
char b = 'u00B2';
mystring = "25";
mystring.append(1,b);
How do you go back the other way? If I extract the 25 and the ² separately, how do I get the unicode number for ² ?
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Nov 18, 2014
Here is what i have so far:
#include<fstream>
#include<iostream>
#include<string>
[Code].....
I also need to do a loop that scan the count array and check if the element is bigger than the previous one.
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Oct 10, 2014
I want to read a string of unknown length from stdin. I tried to follow the approach from this link. URL....My code is like this:
#include <iostream>
#include <string>
using namespace std;
int n;
cin >> n;
cout << "The value of n is " << n << endl;
}
[code]......
What I have noticed is that if I take integer input from cin (cin >> n;) in the above code before getline, the control does not stop on getline to take str as input from the console. If I don't do (cin >> n) before getline then the control stops on getline and takes the string as input.What is the best way to read from console multiple strings of unknown length in combination with the integers?
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