# How to write multiple if statements

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Arman Kam on 24 Jul 2012
Answered: Goh XinYee on 1 Apr 2019
Can i write more than 3 if statements?
if i can why did i get this error?!
??? elseif source1(i,j)==3;
|
Error: Illegal use of reserved keyword "elseif".
this happens after i use
if source1(i,j)==1;
and
elseif source1(i,j)==2;
plus i want to use if condition for seven times!
##### 2 CommentsShowHide 1 older comment
Jan on 25 Jul 2012
Arman has posted the code and accepted it by accident. I've deleted this answer and moved the code to the comment section, because it is not useful to explain the actual problem.
site=[60.5,31.5];
Mmin=4;
DM=0.1;
c1=-1.09;
c2=0.238;
c3=-1;
c4=-0.0005;
sigma=0.15;
sumNy=zeros(1,1.5/0.01);
CellArea=0.01*112.2*0.01*96.3;
for i=1:521
for j=1:400
if source(i,j)~=-9999;
Celldecimal=[(57.935+(j-1)*0.01),(34.108-(i-1)*0.01)];
R= acos(sin(site(1,2)*pi/180)*sin(Celldecimal(1,2)*pi/180)+cos(site(1,2)*pi/180)*cos(Celldecimal(1,2)*pi/180)*cos((Celldecimal(1,1)-site(1,1))*pi/180))*6371;
if source1(i,j)==1;
a=-1.6739;
b=0.6531;
Mmax=7.8;
Davg=17;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==2;
a=-0.2525;
b=1.1351;
Mmax=5.7;
Davg=16;
beta=b*log(10);
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==3;
a=-1.2474;
b=0.8548;
Mmax=6.3;
Davg=20;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==4;
a=-1.1237;
b=0.8127;
Mmax=7.1;
Davg=18;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==5;
a=-1.4385;
b=0.7444;
Mmax=7;
Davg=19;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==6;
a=-1.6544;
b=0.6865;
Mmax=7.8;
Davg=23;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
elseif source1(i,j)==7;
a=-0.9803;
b=0.8746;
Mmax=6.2;
Davg=22;
beta=b*log(10);
NM0=10^(a)*CellArea;
NMmin=NM0*(exp(-beta*Mmin)-exp(-beta*Mmax))/(1-exp(-beta*Mmax));
r=sqrt(R^(2)+Davg^(2));
for PGA=0.01:0.01:1.5
Nymatrix=zeros((7.9-Mmin+DM)/DM,1);
for aa=Mmin:0.1:Mmax
Mmean=aa+0.05;
Freq=NMmin*(exp(-beta*(aa-Mmin))-exp(-beta*((aa+0.1)-Mmin)))/(1-exp(-beta*(Mmax-Mmin)));
loga=log10(PGA);
logamean=c1+c2*Mmean+c3*log10(r)+c4*r;
lognormal=1-normcdf(loga,logamean,sigma);
Ny=Freq*lognormal;
if aa==Mmin
Nymatrix((aa-Mmin+DM)/DM,1)=Ny;
else
Nymatrix(round((aa-Mmin+DM)/DM),1)=Ny+Nymatrix(round((aa-Mmin)/DM),1);
end
end
sumNy(1,round(PGA/0.01))=sum(Nymatrix,1)+sumNy(1,round(PGA/0.01));
end
end
end
end
end
Y=0.01:0.01:1.5;
loglog(sumNy,Y);
axis([.0001 .01 .01 1.5])

C.J. Harris on 24 Jul 2012
Edited: C.J. Harris on 24 Jul 2012
You have too many 'end' statements within your code. An if-else statement should be formatted like this:
if a == 1
% Code
elseif a == 2
% Code
elseif a == 3
% Code
else
% Code
end
In your code however you appear to have put an 'end' before each 'elseif' statement which is resulting in the error you are seeing.
##### 2 CommentsShowHide 1 older comment
Jan on 25 Jul 2012
I've accepted this answer for you.

Leah on 24 Jul 2012
looks like you have an end before all your elseif's that shouldn't be there. It helps to smart indent your code when doing nested if's. Press Ctrl+A (select all) then Ctrl+I (smart indent). The structure of your code seems to be
if source(i,j)==2
% bunch of code
else if source(i,j)==3
% bunch of code
else if source(i,j)=4
% bunch of code
end
end
end
Notice all of the end go at the bottom. To clean this up you might want to use a switch case statement. which would look like this
switch source(i,j)
case 2
% bunch of code
case 3
% bunch of code
case 4
% bunch of code
case 9999
% bunch of code
case otherwise
% bunch of code
end

Goh XinYee on 1 Apr 2019
nono, it is that there is a difference between
else if
and
elseif
...
it is not correct to type else if, as with every 'if', we need an 'end', which is why the program won't run with only one 'end'.
if
else if
else if
end
end
end
however, it is not that case with 'elseif', there is only one 'if' with many 'elseif' (s), and thus only one 'end' is needed.
if
elseif
elseif
end