How to make the indentifier "tortuga" not to be undefined?-CodePudding

I want to create this function:

void drawSquare(int x) {
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
}

However, I get that the identifier "tortuga" is undefined.

I tried to modify the function like this:

void drawSquare(int x) {
    ct::TurtleScreen scr;
    scr.bgcolor({ "white" });
    ct::Turtle tortuga(scr);
    Home(tortuga);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.pencolor({ "red" });
    tortuga.speed(ct::TS_FASTEST);
    scr.exitonclick();
}

I get that the identifier "tortuga" is defined now, which seems to work.However, 20ish windows appeared where in each window, the turtle only drew three sides of a square like the following image: image I expected a spiral to be drawn.

Here is all the program:

#include"CTurtle.hpp"
#include <iostream>
using namespace std;
#define Home(x) x.left(90)

namespace ct = cturtle;
int shellSize;
int initialShellSize;



void drawSquare(int x) {
    ct::TurtleScreen scr;
    scr.bgcolor({ "white" });
    ct::Turtle tortuga(scr);
    Home(tortuga);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.pencolor({ "red" });
    tortuga.speed(ct::TS_FASTEST);
    scr.exitonclick();
}

int main(int argc, char** argv) {
    std::cout << "Type the size of the outershell of the spiral: "; // Type a number and press enter
    std::cin >> shellSize; // Get user input from the keyboard
    initialShellSize = shellSize;
    
    for (int i = 10; i <= initialShellSize; i = i   10)
    {
        shellSize = initialShellSize - (initialShellSize/i);
        drawSquare(shellSize);
    }
    
    return 0;
}

CodePudding user response：

I've never used this library before, but it seems all you need to do is add a turtle parameter to your function and pass the turtle object to the function. This is not dissimilar to what you've already done with the x parameter. Parameter passing is a basic technique of the C language (and pretty much any programming language).

void drawSquare(ct::Turtle& tortuga, int x) {
    Home(tortuga);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
    tortuga.right(90);
    tortuga.forward(x);
}

int main(int argc, char** argv) {
    std::cout << "Type the size of the outershell of the spiral: "; // Type a number and press enter
    std::cin >> shellSize; // Get user input from the keyboard
    initialShellSize = shellSize;
    
    ct::TurtleScreen scr;
    scr.bgcolor({ "white" });
    ct::Turtle tortuga(scr);
    for (int i = 10; i <= initialShellSize; i = i   10)
    {
        shellSize = initialShellSize - (initialShellSize/i);
        drawSquare(tortuga, shellSize);
    }
    
    return 0;
}

I've used a reference ct::Turtle& tortuga instead of ct::Turtle tortuga. I'm guessing that is right, but as I said I've never used this library before.

And as already mentioned to get a square I'm guessing you need to call forward four times.

I've also put the call to Home inside the function, you might disagree.