C++ :: Unable To Extract Unsigned Values From Input Stream
Jan 16, 2015
I am trying to extract unsigned values from an input stream. I expect the extraction to fail when an invalid character is extracted. It fails correctly when I try to extract an unsigned int from "abc", but when I try to extract an unsigned in from "-1", the extraction succeeds, and the max unsigned int value is extracted (as if -1 were cast to unsigned int). I would expect the '-' to cause the extraction of an unsigned value to fail.
The code I am using is below.
#include <iostream>
#include <sstream>
#include <string>
#include <limits>
int main() {
unsigned int value = 8;
std::string negString = "-1";
[Code]...
Is this standard behavior for an istream extractor?
I am trying this in both Linux (gcc 4.4.3) and in windows with Code::Blocks (whaterver came with CB 13.12, apparently gcc 4.7.1)
I have an embedded microcontroller system communicating with a similar system by radio. The api for the radio requires data to be transmitted as an unsigned char array. It will always transmit a positive integer in the range 0 to 255.When I receive the data I am having difficult in extracting this positive integer.
Code: unsigned char rxData[4]={'1','2','3',''}; int inVal=0;
//want to assign inVal whatever number was transmitted
E.g. 123
I've been at this for a week and have tried at least 10 different approaches including the use of the atoi(), copying the absolute value of each element of rxData into another char array, reinterpret_cast, and others.
I am trying to write a function that extracts chunks of numbers from a stream (ie if i had "ui33ui24ui23hjdwejf" it would extract the chunk 33), and its finished, but it wont compile. errors here: [URL] ...... its only one line in an include file, but im stumped. anyways, this is the most updated version of the code: [URL] .....
I have an array matrix called tmat,,and i know that in every row of tmax there are values which repeat two times...and am writing a code to extract the values WHICH DOES NOT REPEAT into another matrix called tcopy...the codes compiles fine...and it writes nicely to file...but without the desired result...
One last question...how can i get the array tcopy written to file in the form 5x3...and not all the figures in line one after the other? i mean i wish to see the matrix like a matrix on file..not like a list of numbers....
Code: #include <iostream> #include <fstream> #include <vector> using namespace std; const int R = 5; const int C = 5;
I am trying to write down in binary format an array of unsigned int values but i get the following compilation error :
: In function ‘int CIndex(std::fstream&, std::fstream&, std::fstream&, std::fstream&)’: ./src/IndexBuilder/index.cpp:23:26: error: no matching function for call to ‘std::basic_fstream<char>::write(int*, long unsigned int)’ ./src/IndexBuilder/index.cpp:23:26: note: candidate is: /usr/include/c++/4.6/bits/ostream.tcc:184:5: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::write(const _CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>, std::streamsize = long int]
This is the part the is not working:
Code: // uia is : unsigned int * uia; // then I have allocated the space for it // load it with unsigned int's // k is the number of variables in my array
o.write(uia,sizeof(unsigned int)*k); But thsi should be so simple and strait forward.... in c i do it as :
Code: fwrite(uia, sizeof(unsigned int), k , fp); but since i would need to convert fstream to FILE* i decided to do it c++ way.
Where col is a 'vec4' struct with a double[4] with values between 0 and 1 (this is checked and clamped elsewhere, and the output is safely within bounds). This is basically used to store rgb and intensity values.
Now, when I add a constant integer as a pixel value, i.e.:
buffer_rgb[i] = ((unsigned char)255;
Everything works as it should. However, when I use the above code, where col is different for every sample sent to the buffer, the resulting image becomes skewed in a weird way, as if the buffer writing is becoming offset as it goes.
You can see in the 'noskew' image all pixels are the same value, from just using an unchanging int to set them. It seems to work with any value between 0-255 but fails only when this value is pulled from my changing col array.
Whole function is here:
// adds sample to pixel. coordinates must be between (-1,1) void Frame::addSample(vec4 col, double contrib, double x, double y) { if (x < -1 || x >= 1 || y < -_aaspect || y >= _aaspect) {
I'm trying to load a file input stream to load all the character content into a variable (say from a .java file for example), but for some reason whenever I type in the name of the file I want to stream I get the report: RUN FAILED (exit value 1, total time 2s)
What is the traditional way to monitor a blocking subroutine that is using a file stream as its input? That is, what is the traditional way to make a progress meter in the console?
Say I have a function that takes in a filestream and works with it. Suppose this file stream has a position and length property like in C# FileStream:
Code:
void sub (filestream file) { //read a bit of the stream, which advances stream cursor position //do something //repeat until all of file stream has been used up }
Presumably the function is chomping along the file stream as it is doing some calculations serially on the file stream.Because the function is blocking, there is no way to access the file streams position and length in this thread. So naturally it seems like the best thing to do to monitor the progress of that function is to make another thread and pass it the file stream object as a parameter, and in this separate thread, monitor the distance between filestream's position and length to determine how much of the file stream has been used up, and every second or so output the amount of file stream used onto the console.
How can i write a function that will read an "unsigned integer" into a variable of type "unsigned short int"? i can not use cin >> inside the function.. so i am looking for atleast a hint!
I wrote a program to write text contents to file stream through fputs, the file stream address was changed in the middle of writing text content to the stream (11% text content have been put into the file stream), that cause the file stream pointer can be evaluated problem and raise exception on stream validation code in fputs library function, my question is what things could go wrong to make file stream pointer changed its address to something else or a NULL pointer if the file stream have not been flushed and closed.
I am trying to assign the integer value to unsigned char array. But it is not storing the integer values. It prints the ascii values. Here the code snippet
The values which are stored in uc[] is ascii values.I need the integer values to be stored in uc[]. I tried to do it with sprintf. but the output is not as expected. if I print the uc[i] it should diplay the value as 0,1,2....99.
I'm having some problems with Input to an array from a file. I think that i need to make a new array for every instance of the loop but i can't figure out how.
I am unable to input the correct form for matrices multiplication. I have an exam tomorrow in which I need to use this.
Code:
#include <stdio.h> #include <conio.h> int main() { float a[10][10], b[10][10], c[10][10]; int i, j, k, l, n=0, m=0, x=0, y=0, sum=0; printf("Enter the number of rows and collumns of the first matrix"); scanf("%d %d", &n, &m);
I'm having issues trying to input data from a .txt file into my array program. The whole program takes the name, # of goals and assists, adds them together to get points, and then puts in a given + or - rating. The program works except for the data input.
Also, this is an alphabetical "Unsorted" list, but is there a way to order the list based on point value and be able to display that as well as a separate "Ordered" list?
And this is the .txt file. Order is Players Name, Goals, Assists, Plus/Minus rating. The points are added when points = goals + assists (Should be in the main coding above).
I am trying to create a simple interface on console to allow to input some values to some variables. For ex:
int main() { double a = 1.5; double b = 2.5; double c = 3.5; string x;
[Code] ....
However, I want these three to display at the same time (now they display one by one), and in the console window I can move the cursor between input place of a, b and c with "arrow key" of keyboard.
I have a problem with how to print out all the numbers that the user enters the code looks like this so far:
Code: #include <iostream> using namespace std; int main()
[Code] ....
I want the program to print out all the numbers that the user has entered after the program have said the higest and lowest number is ?. But I do not know how to do this I thought it could be something like this:
Code: cout << input[0]; //or cout << input[i]; /*
Because i is the number of how many enters of numbers the user can do*/ But that was totally wrong tried to do another "for loop" in the first for loop but that was meaningless because it can't change anything in the first "for loop".
gore calculates x^(2*i)-3 and dole is for (2+i)! for input x=1 and n=1 i get -2.0 output which is the value of x^(2*i)-3 the (2+i)! part gets ignored for some reason, for any other input i tried the output is 0 ....
