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C++ Update console output
(4 answers)
Closed 5 years ago.
I'm developing some application in which I want to manipulate some data comming from the embedded system. So, what do I want to do is that I want to display the values which are comming on the same position where they were before, leaving the static text on the same place and not using new line. Being more specific, I want to output my data in form of a table, and in this table on the same positions I want to update that data. There is some analogy in Linux, when in the terminal there is some update of the value(let's say some progress) while the static text remains and only the value is changing.
So, the output should look like this:
Some_data: 0xFFFF
Some_data2: 0xA1B3
Some_data3: 0x1201
So in this case, "Some_data" remains unchanged on the same place, and only the data itself is updated.
Are there maybe some libraries for doing that? What about Windows Console Functions? Also, it would be very nice if it could be made in such a way, in which the console would not flick, like when you clear the console and print something back. Any hints or suggestions? Thanks very much in advance guys!
P.S. There is no need to write the code, I just need some hints or suggestions, with very short examples if possible(but not required).
On a *nix system you have two options.
1) If you want to manipulate the entire console in table form like you ask, then ncurses is the best option. The complete reference can be found here.
As you can see, that package is quite heavyweight and can often be overkill for simple projects, so I often use . ..
2) If you can contain your changing information on a single line, use the backspace escape char \b and then rewrite the information repeatedly to that line
For example, try this . . .
#include <iostream>
#include <chrono>
#include <thread>
using namespace std;
void writeStuff(int d)
{
cout << string(100,'\b') << flush;
cout << "Thing = " << d;
}
int main()
{
cout << "AMAZING GIZMO" << "\n============" << endl;
while(1) {
writeStuff(rand());
this_thread::sleep_for(chrono::milliseconds(250));
}
}
For a real world example, the sox audio console playback command uses this technique to good effect by displaying a bar chart made of console characters to represent the audio playback level in real time.
Of course, you can get more creative with the method shown above if your console supports ANSI escape sequences.
Related
I'm a beginner coder making a simple text 'choose your own adventure' game, but I want it to scroll out the text like an RPG instead of just spitting out the text. How can I do that?
I believe that the ncurses library is exactly what you are looking for. It allows you lower access to the terminal text, to produce things like full screen text, like this:
A tutorial for how to use it can be found here, and you can download version 6.3 here.
It is used in many applications, like GNU nano. A full list of applications using ncurses can be found here.
I'm going to assume you're just supposed to write to a console.
std::string str = "Your text";
for(char& current_char : str) {
std::cout << current_char << std::flush;
sleep(1000);
}
std::cout << std::endl;
The for loop is going to iterate over each character in the string.
It will then output it to cout. std::flush is here to force the output to be update without using std::endl which would return carriage and we don't want that.
sleep will pause for an amount of time in milliseconds, here 1000 milliseconds (1 second). Be careful though; sleep is a Windows function. On Linux, use usleep. If you need it to be cross-platform you should probably use the thread sleeping functions or make something yourself with chrono.
And finally, we use std::endl to return carriage and update the output.
Alright, I'm a little bit (honestly way too) confused about how the heck I can make a program interact with another program.
For example, let's say a game, a shooter, when you run an external program and you make your character not able to die, or immediately shoot when detects an enemy, etc...
I was reading a little bit about it, and they say you have to know how the "target" is composed. But I still don't get it.
For example, let's say we've got a simple code like this:
#include <iostream>
#include <windows.h>
int main() {
for(int h = 0; ; h++) {
std::cout << "The H's value is: " << h << std::endl;
Sleep(1000);
}
return 0;
}
Then, how do I create another program where I can change the H's value to zero everytime I press any key?
Don't get me wrong, I ain't trying to hack anyone or anything, I'm just curious about how those programs work.
(Sorry if I've got some grammar issues, English isn't my native language).
Specific to your program in the exapmle if we take that the program is already compiled and you are not allowed to make any changes to the source code the solution would be to build a program which will run with high enough privileges to examine this process's memory and directly change the in-memory value of h, which should be on the top of the stack(or almost).
Speaking of some more "legal" ways to do so you should check you should read about inter process communication which can be done with multiple methods. Read this.
However most "Bots" and programs which help cheaters in games are in many cases graphics based and are able to analyse the image and thus help aim. On the other hand some "recoil reducers" simply move your mouse in the opposite direction of the recoil of the gun in game. So there is a ton of approaches to your question and for every particular case the answer might be different.
In C++, when writing to and taking information from the console using cout / cin, is it possible to do something like
ENTER YOUR DATA HERE --> __ <-- ENTER YOUR DATA HERE
With the user input cursor where the underscores are located, and output located on either side of the cursor, and then the user's typed input appearing between those two bits of output before being returned to cin?
If so how would I got about doing that?
I hope that between my title and explanation here that it's clear what I'm asking, if not I can try to explain further.
Ideally I'd like to do this using iostream / cin & cout, because those are what I've used in the past. If the solution is to use... printf or similar I'll do that but may need a bit of additional explanation since I'm not really experienced in using that for output.
NOTE: I tried to find an answer for this problem and I can't say for sure that there wasn't one, it was mostly just a matter of finding a huge amount of other input/output-related questions.
EDIT: This is using the DOS shell on Windows 7, compiling from the Windows Visual Studio 2012 command-line compiler.
If Windows, use the Console API. http://msdn.microsoft.com/en-us/library/windows/desktop/ms682073(v=vs.85).aspx
If Linux, use the curses library: http://en.wikipedia.org/wiki/Ncurses
If you are using windows you have the option to use the conio.h.
#include<iostream.h>
#include<conio.h>
int main()
{
clrscr();
gotoxy(5,3);
cout<<"HELLO WORLD";
gotoxy(60,10);
cout<<"HELLO WORLD";
gotoxy(35,20);
cout<<"HELLO WORLD";
getch();
return 0;
}
If you wish to use ANSI libraries only, you can try to take a look at this discussion:
http://www.cplusplus.com/forum/lounge/78225/
In both cases all you have to do is print the first text, then use gotoxy, then you print seconde text, gotoxy again where you want the input to happens, and read the user input.
Well, the question may sound a bit too vague but here's 2 things I need to do and I'd definitely need some input on this :
Output something (e.g. using cout) with color (note: My TERM environment variable is set to xterm-color if that makes any difference; also, is there any uniform way to output colored text that's compatible with both pure mac and *nix terminals in general, so that the code is portable)
Output something at the same position on the terminal screen. OK, this may sound confusing too. Let's take a terminal app which simply outputs a progress percentage. It normally won't start a new line for that. The new value is shown at the very same spot. How is this doable? (Being a once Borland Pascal guy from the good old DOS days, the only thing I could think of is something to do with accessing video memory directly... or not?)
So... any ideas?
You probably want to use ncurses library. And ANSI escape codes can also be used for coloring.
1)
You can try Color cout , but that is not protable. I tried (ANSI escape codes) something like
cout << "\033[1;31mbold red text\033[0m\n";
cout << "\33[0;31m" << "Enter Your String here" << "\33[0m" << std::endl ;
You can also look at
How do I output coloured text to a Linux terminal?
2)
Are you looking for something like watch or top like app which are showing output at the same spot.
I'd like to have my program output "cm2" (cm squared).
How do make a superscript 2?
As Zan said, it depends what character encoding your standard output supports. If it supports Unicode , you can use the encoding for ²(U+00B2). If it supports the same Unicode encoding for source files and standard output, you can just embed it in the file. For example, my GNU/Linux system uses UTF-8 for both, so this works fine:
#include <iostream>
int main()
{
std::cout << "cm²" << std::endl;
}
This is not something C++ can do on its own.
You would need to use a specific feature of your console system.
I am not aware of any consoles or terminals that implement super-script. I might be wrong though.
I was trying to accomplish this task for the purpose of making a quadratic equation solver. Writing ax² inside a cout << by holding ALT while typing 253 displayed properly in the source code only, BUT NOT in the console. When running the program, it appeared as a light colored rectangle instead of a superscript 2.
A simple solution to this seems to be casting the integer 253 as a char, like this... (char)253.
Because our professor discourages us from using 'magic numbers', I declared it as a constant variable... const int superScriptTwo = 253; //ascii value of super script two.
Then, where I wanted the superscript 2 to appear in the console, I cast my variable as a char like this...
cout << "f(x) = ax" << (char)superScriptTwo << " + bx + c"; and it displayed perfectly.
Perhaps it's even easier just to create it as a char to begin with, and not worry about casting it. This code will also print a super script 2 to the console when compiled and run in VS2013 on my Lenovo running Windows 7...
char ssTwo = 253;
cout << ssTwo << endl;
I hope someone will find this useful. This is my first post, ever, so I do apologize in advance if I accidentally violated any Stack Overflow protocols for answering a question posted 5+ years ago. Any such occurrence was not intentional.
Yes, I agree with Zan.
Basic C++ does not have any inbuilt functionality to print superscripts or subscripts. You need to use any additional UI library.
std::cout << cm\x00B2;
writes cm^2.
For super scripting or sub scripting you need to use ascii value of the letter or number.
Eg: Super scripting 2 for x² we need to get the ascii value of super script of 2 (search in google for that) ie - 253. For typing ascii character you have to do alt + 253 here, you can write a any number, but its 253 in this case.
Eg:-cout<<"x²";
So, now it should display x² on the black screen.
Why don't you try ASCII?
Declare a character and give it an ASCII value of 253 and then print the character.
So your code should go like this;
char ch = 253;
cout<<"cm"<<ch;
This will definitely print cm2.