LEDA programming with c++: - c++

I am a LEDA-6.3 user.
I have an error when compiling this simple code:
#include <LEDA/core/d_array.h>
#include <iostream>
using namespace std;
main()
{
d_array<string,string> dic;
dic["hello"] = "hallo";
dic["world"] = "Welt";
dic["book"] = "Buch";
dic["key"] = "Schluessel";
string s;
forall_defined(s,dic) cout << s << " " << dic[s] << endl;
}
G++ Compiler:
g++ -I$LEDAROOT/incl -L$LEDAROOT d_array.cpp /usr/lib/LEDA/libleda.a -lX11 -lm -o d_array
The ERROR:
d_array.cpp: In function ‘int main()’:
d_array.cpp:8: error: ‘d_array’ was not declared in this scope
d_array.cpp:8: error: expected primary-expression before ‘,’ token
d_array.cpp:8: error: expected primary-expression before ‘>’ token
d_array.cpp:8: error: ‘dic’ was not declared in this scope
Please if there is a guide for LEDA-6.3 give me the link

You probably mean leda::d_array or are forgetting using namespace leda;

Related

Getting an weird error in vscode when i'm trying to run a code

When I'm trying to run a simple hello world script it sends this error message, Can anyone help me solving this issue?
[Running] cd "c:\Users\NickT\OneDrive\Documents\C++ Tutorial\" && g++ helloworld.cpp -o helloworld && "c:\Users\NickT\OneDrive\Documents\C++ Tutorial\"helloworld
helloworld.cpp: In function `int main()':
helloworld.cpp:9: error: expected primary-expression before "msg"
helloworld.cpp:9: error: expected `;' before "msg"
helloworld.cpp:11: error: expected primary-expression before "const"
helloworld.cpp:11: error: expected `;' before "const"
helloworld.cpp:16: error: expected primary-expression before '}' token
helloworld.cpp:16: error: expected `)' before '}' token
helloworld.cpp:16: error: expected primary-expression before '}' token
helloworld.cpp:16: error: expected `;' before '}' token
[Done] exited with code=1 in 0.233 seconds
This is the written code
#include <iostream>
int main(){
std::cout << "Hello World" << std::endl;
return 0;
}
I revised the code you have posted as well as added a piece of code to utilize the namespace std. Analyzing the output from your compiler it does seem that you may have not added a semi colon. Alternatively, it's not necessary to reference the std library when calling it's functions but it's up to your preference. It doesn't seem though to be an issue with your code either. Can you post the actual code you've attempted to compile because there doesn't seem to be an issue with this piece.
Revised Code:
#include <iostream>
using namespace std;
int main() {
std::cout << "Hello World" << std::endl;
return 0;
}

Expression list treated as compound expression

I'm trying to compile a program I got from the net. Trying to use in codeblocks but its showing errors. I don't understand what is going wrong. I've looked up in various forums but not much light is shed. Can anyone help soon? Thanks in advance
#include <functional>
#include <iostream>
int print_num(int i, int j) { return i + j; }
int main() {
std::function<int(int, int)> foo = print_num;
std::function<int(int, int)> bar;
try {
std::cout << foo(10, 20) << '\n';
std::cout << bar(10, 20) << '\n';
} catch (std::bad_function_call& e) {
std::cout << "ERROR: Bad function call\n";
}
return 0;
}
These are some of the errors other than 14 other errors saying declaration not done. I guess clearing these error would solve that problem.
main.cpp|10|error: 'function' is not a member of 'std'
main.cpp|10|error: expression list treated as compound expression in functional cast [-fpermissive]
main.cpp|10|error: expected primary-expression before 'int'
You need to compile with -std=c++11 to add in the C++11 features.
$ g++ -std=c++11 test.cxx && ./a.out
30
ERROR: Bad function call
vs:
$ g++ test.cxx && ./a.out
test.cxx: In function ‘int main()’:
test.cxx:10:3: error: ‘function’ is not a member of ‘std’
test.cxx:10:28: error: expression list treated as compound expression in functional cast [-fpermissive]
test.cxx:10:17: error: expected primary-expression before ‘int’
...

SFML VertexArray not member of sf

I have the following program for drawing a triangle with vertex arrays, as described in SFML tutorials.
#include <SFML/Graphics.hpp>
#include <iostream>
int main()
{
try{
sf::RenderWindow Mywindow(sf::VideoMode(800,600),"TriColor Triangle!");
sf::VertexArray triangle(sf::Triangles, 3);
triangle[0].position = sf::Vector2f(5,5);
triangle[1].position = sf::Vector2f(50,5);
triangle[2].position = sf::Vector2f(50,50);
triangle[0].color = sf::Color::Red;
triangle[1].color = sf::Color::Blue;
triangle[2].color = sf::Color::Green;
Mywindow.draw(triangle);
}
catch( const std::runtime_error& e)
{
std::cout << e.what() << std::endl;
std::cin.ignore();
return EXIT_FAILURE;
}
std::cin.ignore();
return EXIT_SUCCESS;
}
The Makefile for compilation I am using is the following:
all: exe
exe: main.o
g++ main.o -o exe -lsfml-graphics -lsfml-window -lsfml-system
main.o: main.cpp
g++ -c main.cpp
The follwing error is being displayed:
make
g++ -c main.cpp
main.cpp: In function ‘int main()’:
main.cpp:11:2: error: ‘VertexArray’ is not a member of ‘sf’
main.cpp:11:18: error: expected ‘;’ before ‘triangle’
main.cpp:13:2: error: ‘triangle’ was not declared in this scope
main.cpp:21:11: error: ‘class sf::RenderWindow’ has no member named ‘draw’
main.cpp:23:33: error: expected unqualified-id before ‘&’ token
main.cpp:23:33: error: expected ‘)’ before ‘&’ token
main.cpp:23:33: error: expected ‘{’ before ‘&’ token
main.cpp:23:35: error: ‘e’ was not declared in this scope
main.cpp:23:36: error: expected ‘;’ before ‘)’ token
make: *** [main.o] Error 1
I don't understand why it is saying VertexArray not member of sf!
You must provide a path to the SFML lib dir and a path to the SFML include dir.
Like this:
"-IC:\\Path\\to\\your\\project\\your-lib-sub-dir\\SFML-2.1\\include"
"-LC:\\Path\\to\\your\\project\\your-lib-sub-dir\\SFML-2.1\\lib"
Another thing, to be able to see something, you should suround your draw call with something like this:
while(1){
Mywindow.clear(sf::Color::Black);
Mywindow.draw(triangle);
Mywindow.display();
}

G++ doesn't compile C++0x range-based for loop

I was experimenting with some of the new C++0x features with G++. Lambdas, auto, and the other new features worked like a charm, but the range-based for-loop failed to compile. This is the program I was testing:
#include <iostream>
#include <vector>
int main ()
{
std::vector<int> data = { 1, 2, 3, 4 };
for ( int datum : data )
{
std::cout << datum << std::endl;
}
}
I compiled it with:
g++ test.cpp -std=c++0x
I also tried gnu++0x, but the output was the same.
This was the output:
test.cpp: In function ‘int main()’:
test.cpp:8:21: error: expected initializer before ‘:’ token
test.cpp:12:1: error: expected primary-expression before ‘}’ token
test.cpp:12:1: error: expected ‘;’ before ‘}’ token
test.cpp:12:1: error: expected primary-expression before ‘}’ token
test.cpp:12:1: error: expected ‘)’ before ‘}’ token
test.cpp:12:1: error: expected primary-expression before ‘}’ token
test.cpp:12:1: error: expected ‘;’ before ‘}’ token
Thanks in advance for your help.
EDIT: I am using GCC version 4.5.2, which I now see is too old.
You need GCC 4.6 and above to get range-based for loops.
GCC's C++0x status
$ cat for.cpp
#include <iostream>
int main()
{
for (char c: "Hello, world!")
std::cout << c;
std::cout << std::endl;
return 0;
}
$ g++ -std=c++0x -o for for.cpp
$ ./for
Hello, world!
$ g++ --version
g++ (GCC) 4.6.1 20110325 (prerelease)

Unable to compile simple jsoncpp program with Eclipse on LInux

The File is at the location /home/shivang/Desktop and the filename is sh1.cpp
Source code for the file is given below
#include iostream
#include json/json.h
#include json/reader.h
using namespace std;
using namespace Json;
int main() {
std::string example = "{\"array\":[\"item1\", \"item2\"], \"not an array\":\"asdf\"}";
Value value;
Reader reader;
bool parsed = reader.parse(example, value, false);
std::cout << parsed;
cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
return 0;
}
The following error messages are displayed.
/home/shivang/Desktop/sh1.cpp: In function ‘int main()’:
/home/shivang/Desktop/sh1.cpp:10:2: error: ‘Value’ was not declared in this scope
/home/shivang/Desktop/sh1.cpp:10:8: error: expected ‘;’ before ‘value’
/home/shivang/Desktop/sh1.cpp:11:2: error: ‘Reader’ was not declared in this scope
/home/shivang/Desktop/sh1.cpp:11:9: error: expected ‘;’ before ‘reader’
/home/shivang/Desktop/sh1.cpp:13:16: error: ‘reader’ was not declared in this scope
/home/shivang/Desktop/sh1.cpp:13:38: error: ‘value’ was not declared in this scope
Configuration gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)
jsoncpp-src-0.5.0
eclipse-cpp-helios-SR2-linux-gtk
I have never used Json or C++ before. But a little googling around led me to this page. I think adding the following line to your list of includes should help:
#include <json/value.h>