for(int i=0,j=10; i=j=10; i++,j--)

This code snippet is not valid as the conditional statement in the for loop is not properly defined. The statement "i=j=10" is not a valid comparison operator.

A valid for loop statement would have a comparison operator in the conditional statement, such as:

for(int i=0,j=10; i<10 && j>0; i++,j--) {
// loop code here
}

This loop will run as long as i is less than 10 AND j is greater than 0. The loop code will execute each time the loop iterates.