Why Does My Code Work for Fprintf, but not disp() for outputting a result from the user input

Hello, I recently was using MatLab and ran into an error consistently that was

"Error using +

Matrix dimensions must agree.

Error in GickRonin_M2_Ch5_part2 (line 39)

disp('Fish caught for WholeFish: ' + WholeFish + 'kg, sold for: ' + WFPrice) "

Here is the code (Jist of it user inputs amount of fish caught, then the weights of the fish depending on weight that is the 'grade' and the 'grade' impacts the $)

This is before I changed the final statement to fprintf

EndIndex = input("What is the # of Fish you have caught? ");
x = 1;
Fish = (1:EndIndex);
while (x <= EndIndex)
    Fish(x) = input('Weight of fish = ');
    x = x + 1; 
end 
WholeFish = 0; 
Fillet = 0;
Canning = 0;
PetFood = 0;
FishExtracts = 0;
% Loop to check for what weight the fish is and assign it to the correct 
% Class of Fish 
for Weight = Fish
    if (Weight > 30)
        WholeFish = WholeFish + Weight; 
    elseif (Weight > 20 && Weight <= 30)
        Fillet = Fillet + Weight;
    elseif (Weight > 10 && Weight <= 20) 
        Canning = Canning + Weight; 
    elseif (Weight > 5 && Weight <= 10)
        PetFood = PetFood + Weight; 
    elseif (Weight <=5) 
       FishExtracts = FishExtracts + Weight;
    end
end 
disp (WholeFish)
%Display the Weights of each weight class as well as the price 
WFPrice = WholeFish * 20;
FPrice = Fillet * 15;
CPrice = Canning * 6;
PFPrice = PetFood * 4; 
FEPrice = FishExtracts; 
TotalPrice = WFPrice + FPrice + CPrice + PFPrice + FEPrice; 
%Checking my variables 
disp ("FishWF: " + WFPrice)
disp('Fish caught for WholeFish: ' +  WholeFish + ' kg, Sold for: ' + WFPrice)

Following me inputting only above 30 lb fish to check it would output the error above,

I then changed the code to

fprintf(' ,%d',WholeFish) and it outputted fine, I am confused as why this is happening.

Answer 1

[Cris LaPierre]

Concatenation with + only works for strings ("string"), not character arrays ('character array').

Replace your single quotes with double quotes in your disp command and it will work.

disp("Fish caught for WholeFish: " +  WholeFish + "kg, Sold for: " + WFPrice)

[Cris LaPierre]

There are other issues with the code, however.

For example, your for loop. You must loop through the values one at a time.

for loop = 1:length(Fish)
    Weight = Fish(loop)
    if...
        ...
    end
end