I want to produce square wave without using square function, but this code it showing error, "illegal use of IF keyword". How to rectify it?

t=-10:0.1:10;
a=1;

for i=1:2:201
  {
      if a==1
    {    
         z(1,i)=0;
         z(1,i+1)=0;
     }   
    else 
      {  
         z(1,i)=1;
         z(1,i+1)=1;
       } 
      end
    a=a*(-1); 
   }  
end
plot(t,z)
 

Answer 1

[Walter Roberson]

In MATLAB, {} is used only for building cell arrays, or extraction of data from collection objects, such as cell arrays or tables or string scalars. You should remove all of those { and } that you have.

Answer 2

[Steven Lord]

In some languages (like C) you need to use {} around sections of code (like the bodies of for loops or if statements.) MATLAB is not one of those languages.

t=-10:0.1:10;
a=1;
for i=1:2:201
      if a==1
         z(1,i)=0;
         z(1,i+1)=0;
    else 
         z(1,i)=1;
         z(1,i+1)=1;
      end
    a=a*(-1); 
end
plot(t,z)

I'll leave it to you to decide what to do about the extra element in z that prevents you from calling plot on t and z.

Based on this mistake (trying to use another language's syntax in MATLAB) I'm guessing you're new to MATLAB. If that's the case, I recommend going through the free MATLAB Onramp tutorial (https://www.mathworks.com/support/learn-with-matlab-tutorials.html) to familiarize yourself with the basics of MATLAB syntax.