how do i use the values read by the eval function in other formulas?

prompt = {'Enter the forces(kN): '};
title = 'Environmental forces';
answer = inputdlg(prompt,title);
f = str2num(answer{:});
for ii=1:numel(f)
    eval(sprintf('f%d = %f\n',ii,f(ii)))
end
prompt1 = {'Enter the respective angles: '};
title1 = 'Angle w.r.t x-axis';
answer1 = inputdlg(prompt1, title1);
a = str2num(answer1{:});
for jj=1:numel(a)
    eval(sprintf('a%d = %f\n',jj,a(jj)))
end
The code above  would read the forces and their respective angles and assign the variables automatically. I want to find the horizontal component. i.e. f*cos(a).. How do i do it?

Answer 1

[rifat]

prompt = {'Enter the forces(kN): '};
title = 'Environmental forces';
answer = inputdlg(prompt,title);
f = str2num(answer{:});
for ii=1:numel(f)
    eval(sprintf('f%d = %f\n',ii,f(ii)))
end
prompt1 = {'Enter the respective angles: '};
title1 = 'Angle w.r.t x-axis';
answer1 = inputdlg(prompt1, title1);
a = str2num(answer1{:});
for jj=1:numel(a)
    eval(sprintf('a%d = %f\n',jj,a(jj)))
end

disp('shows the f*cos(a)');
for jj=1:numel(a)
    string=['f(jj)*cos(a(jj))'];
    eval(string)
end

[DIJESH]

can u please explain how to add the values which is evaluated at the end? i mean wat if i have to add the all the values in the variable 'string'?