Chapter 2.3, Problem 2.32PP

Practice Problem 2.32 (solution page 153)

You are assigned the task of writing code for a function tsub_ok, with arguments x and y, that will return 1 if computing x-y does not cause overflow. Having just written the code for Problem 2.30, you write the following:

/* Determine whether arguments can be subtracted without overflow */

/* WARNING: This code is buggy. */

int tsub_ok(int x, int y) {

return tadd_ok(x, -y)

}

For what values of x and y will this function give incorrect results? Writing a

correct version of this function.is left as an exercise (Problem 2.74).