Doubt regarding nextion

Using Arduino Programming Questions
#1

hello, i have a doubt regarding nextion where i am creating my own calculator where i am facing issues with minus and divison, here the variable which i am storing takes only one value everytime
Here is the code which i have written in GUI of nextion

cov t0.txt,va0.val,0
if(va1.val==1)
{
va3.val=va0.val
cov t0.txt,va2.val,0
va4.val=va2.val
va5.val=va3.val+va4.val
cov va5.val,t0.txt,0
}else if(va1.val==4)
{
va3.val=va0.val
cov t0.txt,va2.val,0
va4.val=va2.val
va5.val=va3.val*va4.val
cov va5.val,t0.txt,0
}
else if(va1.val==2)
{

va3.val=va0.val
//cov t0.txt,va2.val,0
va4.val=va2.val
va3.val=va0.val
va5.val=va3.val-va4.val
cov va5.val,t0.txt,0
}
else if(va1.val==3)
{
va3.val=va0.val
// cov t0.txt,va2.val,0
va4.val=va2.val
va5.val=va3.val/va4.val
cov va5.val,t0.txt,0
}

#2

what do you think the following does?

    cov t0.txt,va2.val,0

why aren't there any semicolons (";") terminating your lines of code?

#3

If you look in https://forum.arduino.cc/index.php?topic=604185.0 there is sample code at the end that includes a simple calculator. However, the calculator runs on the attached Arduino with the Nextion providing the interface. If you want it to be stand alone without an Arduino involved then I can't help.

#4

gcjr:
what do you think the following does?

    cov t0.txt,va2.val,0

why aren't there any semicolons (";") terminating your lines of code?

I think akshathahv has posted code from a Nextion display, not from an Arduino sketch. Nextion displays use a very simplified version of C, which I call C--. No semicolons required.

#5