How to resolve the error of "Consider preallocating for speed" which is coming on executing the program below??

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AVIJIT NEMO on 18 Nov 2020

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https://ch.mathworks.com/matlabcentral/answers/651708-how-to-resolve-the-error-of-consider-preallocating-for-speed-which-is-coming-on-executing-the-pro

Commented: AVIJIT NEMO on 20 Nov 2020

f=input('enter frequency of fundamental');
K=input('enter number of SAMPLES PER CYCLE');
C=input('enter number of cycles required ');
T=1/f;
Ts=T/K;
k=0:1:K*C;
t=(k)*Ts;
v=10*sin(2*pi*f*t+pi/6);
g=2*pi*f*t;
subplot(2,2,1);
plot(t,v)
title('signal without noise');
xlabel('sample nummber');
ylabel(' magnitude');
%calculation of the Vpeak amd phase with two sample window technique WITHOUT noise     
for k=1:1:K*C
    a(1,k+1)=(v(1,k)*cos(g(1,k+1))-v(1,k+1)*cos(g(1,k)))/sin(g(1,k+1)-g(1,k));
    b(1,k+1)=(-v(1,k)*sin(g(1,k+1))+v(1,k+1)*sin(g(1,k)))/sin(g(1,k+1)-g(1,k));
    V(1,k+1)=sqrt(a(1,k+1)^2+b(1,k+1)^2);
    G(1,k+1)=atan(b(1,k+1)/a(1,k+1));
    
end
k=1:1:K*C;
V1(1,k)=V(1,k+1);
mean(V1)
std(V1);
l=1;
%calculation of the Vpeak amd phase with two sample window technique WITH noise     
for E=0.1:0.3:3.0
s=rng;
a=0;b=05;
r = (b-a).*rand(1,length(t)) + a;
rng(s);
vn=10*sin(2*pi*f*t+pi/6)+E*r;
subplot(2,2,2);
j=1:1:length(vn);
plot(j,vn)
title('signal with noise');
xlabel('sample nummber');
ylabel(' magnitude');
for k=1:1:K*C
    a(1,k+1)=(vn(1,k)*cos(g(1,k+1))-vn(1,k+1)*cos(g(1,k)))/sin(g(1,k+1)-g(1,k));
    b(1,k+1)=(-vn(1,k)*sin(g(1,k+1))+vn(1,k+1)*sin(g(1,k)))/sin(g(1,k+1)-g(1,k));
    Vn(1,k)=sqrt(a(1,k+1)^2+b(1,k+1)^2);
    Gn(1,k)=atan(b(1,k+1)/a(1,k+1));
   
    
end
j=1:1:C*K;subplot(2,2,3);
plot(j,Vn);
title('estimated peak with E=3.0');
xlabel('sample nummber');
ylabel('peak magnitude estimated');
M(1,l)=mean(Vn)
p(1,l)=  std(Vn)
l=l+1;
end
%-----------------frequency response-----------------------
for m=1:1:1000
vf=(10)*sin(2*pi*m*t+pi/6);
for k=1:1:K*C
    a(1,k+1)=(vf(1,k)*cos(g(1,k+1))-vf(1,k+1)*cos(g(1,k)))/sin(g(1,k+1)-g(1,k));
    b(1,k+1)=(-vf(1,k)*sin(g(1,k+1))+vf(1,k+1)*sin(g(1,k)))/sin(g(1,k+1)-g(1,k));
    Vf(1,k+1)=sqrt(a(1,k+1)^2+b(1,k+1)^2);
    Gf(1,k+1)=atan(b(1,k+1)/a(1,k+1));
    
end
k=1:1:K*C;
Vf1(1,k)=Vf(1,k+1);
me(1,m)=mean(Vf1);
end
subplot(2,2,4)
m=1:1:1000;
plot(m/50,me);
title('frequency response ');
xlabel('m');
ylabel('magnitude');