kosi_hitac(4)

[a,b]=zad1(17.5,0.01,20,1);

function [v0,alpha]=zad1(xfinal,odstupanje,vmax,crtanje)
    %%Check for number of arguments min. value =1
    if(nargin==0)
        fprintf("Zadatak nije moguce rijesiti\n");
        return;
    end

    %%Gravitational acceleartion
    g=9.81;
    %%Search: fix speed, change angle alpha from pi/4 and divide the
    %%interval to half parts

    %%First check if possible (we'll  take vmax and angle for max distance)

    if(xfinal-vmax*vmax/g>odstupanje)
        fprintf("Zadatak nije moguce rijesiti");
        return;
    end
    %%Optimal launch angle for max. distance is alpha=pi/4
    alpha=pi/4;

    vdonja=0;
    vsredina=vmax/2.;
    v0=vsredina;
    while abs(xfinal-v0*v0/g)>odstupanje
        if xfinal-v0*v0/g<0
            %Polovimo interval 0 - vgranica (prebacaj) smanji
            v0=(vsredina+vdonja)/2.;
            vmax=vsredina;
            vsredina=v0;
        else
            v0=(vsredina+vmax)/2.;
            vdonja=vsredina;
            vsredina=v0;
        end
    end
    if crtanje==1
        x=0:0.01:xfinal;
        y=x.*tan(alpha)-g*x.^2/(2*v0^2*(cos(alpha)^2));
        plot(x,y,'r');
        hold on;
        plot(xfinal,0,'*k');
    end
end