CSC361 HW6

1. Assume the following rules of associativity and precedence for expressions

Precedence:

Highest
*, /, not
+, -
- (unary minus)
=, /=, <, <=, >= , >
and
or, xor
Lowest

Associativity Left to right

Show the order of evaluation of the following expressions by parenthesizing all subexpressions and placing a superscript on the right parenthesis to indicate order. For example, for the expression

a + b * c + d

the order of evaluation would be represented as

((a + ( b * c )1)2 + d)3

• s / t +v * t - v
• (t - s) /v * t
• (a > b) or (not true and false)

2.

Let the function FUN be defined as

int FUN ( int & T )
{
T =T + 2;
return T;
}

Suppose FUN is used in a program as follows

I = 200;
sum1 = FUN( I ) + I * 2;
J = 10;
sum2 = ( J / 2 ) + FUN( J );

What are the values of sum1 and sum2

• if the operands in the expression are evaluated left to right?
• if the operands in the expression are evaluated right to left?

3. Rewrite the following code segment using a loop structure in C/C++

A = T + 2;
Loop:
B = A * 3;
B++;
If (B < 100) goto Loop;
T = T + A;

4. Suppose that C++ did not have short circuiting in Boolean expressions. Rewrite the following code to avoid ever dividing by zero:

cin >> Z >> X;
if ( Z != 0 && X / Z < 3 )
cout << Z;

cout << X;