i have a question about for loops.

Q1:So lets say we have an action in order from x= 0 to x=5 i want the loop to go increment from 0 to 5, how would i make the for loop run from y=5 to 0 in the same for loop? would it be something like this:

for(i=0,j=5 ; i<6,i>=0;i++,j--){

x=i;

y=j;

}

Q2:

is for loop from Q1 same as this:

for(i=0;i<6; i++){

x=i;

}

for(j=5;j>=0;j--){

y=j;

}

Q3: From Q1 can i just make y=~i instead of y=j ?