To get started let's do the usual "Hello World" kind of thing, but for C++. I use a lot of colors in the output of these tools to highlight errors and such, so it might be instructive to show how I do that before we move ahead.
ANSI colors are really nothing to do with C++, but they are fun. Such sequences begin with the escape character (33) and act as instructions to your terminal to turn on colors, underline, bold etc. It all depends on what your terminal can do to get good results. For lots of detail on the types of ANSI codes you can use. See this link Many of these are used in the example below. Anyway, here we go:
#include <iostream>
use namespace std;
std::cout << "\033[31;1;4mHello world\033[0m" << std::endl;This gives us red text (31), bold (1) and underlined (4). To reset back to the terminal default, we send the reset sequence.
We also introduce the "std" namespace here. Some people opt to do
#include <iostream>
use namespace std;but it is considered bad practice to use this. See this link. Personally I agree and find code clearer when it uses "std:" explicitly in the code as you are left in no doubt as to what namespace is being used.
#include <iostream>
use namespace std;
std::cout << ...sends output to the stdout for this process. For errors, you would want to use instead:
#include <iostream>
use namespace std;
std::cerr << "aargh" << ...For newlines, like in C where we had "\n", you have in C++:
#include <iostream>
use namespace std;
... << "aargh" << std::endl;A couple of other things are introduced here, namely strings:
#include <iostream>
#include <string>
use namespace std;
const std::string what = "hello there"; // consts cannot be modifiedAnd vectors e.g.:
#include <iostream>
#include <string>
#include <vector>
use namespace std;
std::vector<std::string> = { "hello", "there" };Other more complex things we'll conver later, like initializer lists.
Ok, so enough background. The output should look like:
And here is the full example.
#include <assert.h>
#include <iomanip>
#include <iostream>
#include <vector>
class Ansi
{
public:
Ansi()
{
const std::initializer_list< std::string > code_strings = {
/* reset */ "\033[0m",
/* bold */ "\033[1m",
/* faint */ "\033[2m",
/* italic */ "\033[3m",
/* underline */ "\033[4m",
/* slow_blink */ "\033[5m",
/* rapid_blink */ "\033[6m",
/* reverse_video */ "\033[7m",
/* conceal */ "\033[8m",
/* crossed_out */ "\033[9m",
/* primary_font */ "\033[10m",
/* alt_font1 */ "\033[11m",
/* alt_font2 */ "\033[12m",
/* alt_font3 */ "\033[13m",
/* alt_font4 */ "\033[14m",
/* alt_font5 */ "\033[15m",
/* alt_font6 */ "\033[16m",
/* alt_font7 */ "\033[17m",
/* alt_font8 */ "\033[18m",
/* alt_font9 */ "\033[19m",
/* fraktur */ "\033[20m",
/* bold_off_or_double_underline */ "\033[21m",
/* normal_color */ "\033[22m",
/* not_italic */ "\033[23m",
/* underline_off */ "\033[24m",
/* blink_off */ "\033[25m",
/* unused */ "\033[26m",
/* inverse_off */ "\033[27m",
/* reveal */ "\033[28m",
/* not_crossed_out */ "\033[29m",
/* foreground_black */ "\033[30m",
/* foreground_red */ "\033[31m",
/* foreground_green */ "\033[32m",
/* foreground_yellow */ "\033[33m",
/* foreground_blue */ "\033[34m",
/* foreground_magenta */ "\033[35m",
/* foreground_cyan */ "\033[36m",
/* foreground_white */ "\033[37m",
/* foreground_color2 */ "\033[38m",
/* default_foreground_color */ "\033[39m",
/* background_black */ "\033[40m",
/* background_red */ "\033[41m",
/* background_green */ "\033[42m",
/* background_yellow */ "\033[43m",
/* background_blue */ "\033[44m",
/* background_magenta */ "\033[45m",
/* background_cyan */ "\033[46m",
/* background_white */ "\033[47m",
/* background_color2 */ "\033[48m",
/* default_background_color */ "\033[49m",
/* unused2 */ "\033[49m",
/* framed */ "\033[51m",
/* encircled */ "\033[52m",
/* overlined */ "\033[53m",
/* not_framed_or_encircled */ "\033[54m",
/* not_overlined */ "\033[55m",
/* unused3 */ "\033[56m",
/* unused4 */ "\033[57m",
/* unused5 */ "\033[58m",
/* unused6 */ "\033[59m",
/* underline2 */ "\033[60m",
/* double_underline */ "\033[61m",
/* overline */ "\033[62m",
/* double_overline */ "\033[63m",
/* stress_marking */ "\033[64m",
/* attributes_off */ "\033[65m",
};
codes = code_strings;
};
//
// Get the ansii escape sequence for the given code
//
std::string get_code(unsigned char code)
{
assert(code < codes.size());
return (codes[ code ]);
}
enum AnsiCode {
RESET = 0,
BOLD = 1,
FAINT = 2,
ITALIC = 3,
UNDERLINE = 4,
SLOW_BLINK = 5,
RAPID_BLINK = 6,
REVERSE_VIDEO = 7,
CONCEAL = 8,
CROSSED_OUT = 9,
PRIMARY_FONT = 10,
ALT_FONT1 = 11,
ALT_FONT2 = 12,
ALT_FONT3 = 13,
ALT_FONT4 = 14,
ALT_FONT5 = 15,
ALT_FONT6 = 16,
ALT_FONT7 = 17,
ALT_FONT8 = 18,
ALT_FONT9 = 19,
FRAKTUR = 20,
BOLD_OFF_OR_DOUBLE_UNDERLINE = 21,
NORMAL_COLOR = 22,
NOT_ITALIC = 23,
UNDERLINE_OFF = 24,
BLINK_OFF = 25,
UNUSED = 25,
INVERSE_OFF = 27,
REVEAL = 28,
NOT_CROSSED_OUT = 29,
FOREGROUND_BLACK = 30,
FOREGROUND_RED = 31,
FOREGROUND_GREEN = 32,
FOREGROUND_YELLOW = 33,
FOREGROUND_BLUE = 34,
FOREGROUND_MAGENTA = 35,
FOREGROUND_CYAN = 36,
FOREGROUND_WHITE = 37,
FOREGROUND_COLOR2 = 38,
DEFAULT_FOREGROUND_COLOR = 39,
BACKGROUND_BLACK = 40,
BACKGROUND_RED = 41,
BACKGROUND_GREEN = 42,
BACKGROUND_YELLOW = 43,
BACKGROUND_BLUE = 44,
BACKGROUND_MAGENTA = 45,
BACKGROUND_CYAN = 46,
BACKGROUND_WHITE = 47,
BACKGROUND_COLOR2 = 48,
DEFAULT_BACKGROUND_COLOR = 49,
UNUSED2 = 49,
FRAMED = 51,
ENCIRCLED = 52,
OVERLINED = 53,
NOT_FRAMED_OR_ENCIRCLED = 54,
NOT_OVERLINED = 55,
UNUSED3 = 56,
UNUSED4 = 57,
UNUSED5 = 58,
UNUSED6 = 59,
UNDERLINE2 = 60,
DOUBLE_UNDERLINE = 61,
OVERLINE = 62,
DOUBLE_OVERLINE = 63,
STRESS_MARKING = 64,
ATTRIBUTES_OFF = 65,
};
private:
std::vector< std::string > codes;
};
int main(int argc, char *argv[])
{
Ansi ansii;
std::cout << std::endl;
std::cout << ansii.get_code(ansii.FOREGROUND_RED);
std::cout << "hello ";
std::cout << ansii.get_code(ansii.FOREGROUND_GREEN);
std::cout << "beautiful";
std::cout << ansii.get_code(ansii.RESET);
std::cout << ansii.get_code(ansii.FOREGROUND_CYAN);
std::cout << " colorful";
std::cout << ansii.get_code(ansii.RESET);
std::cout << ansii.get_code(ansii.FOREGROUND_BLUE);
std::cout << " world";
std::cout << ansii.get_code(ansii.RESET);
std::cout << " from C++";
std::cout << std::endl;
return (0);
}To build:
cd hello_world_color rm -f *.o example clang -std=c++2a -Werror -g -O3 -fstack-protector-all -ggdb3 -Wall -c -o main.o main.cpp clang main.o -lstdc++ -o example