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// RUN: %dafny /compile:0 /print:"%t.print" /dprint:"%t.dprint" "%s" > "%t"
// RUN: %diff "%s.expect" "%t"
method M(x: real)
decreases x;
{
if 0.0 <= x {
M(x - 15.0);
}
}
method N(x: real, y: real)
decreases x, y;
{
if 0.0 <= y {
N(x, y - 1.0);
} else if 0.0 <= x {
N(x - 1.0, 300.0);
}
}
method N_implicitDecreases(x: real, y: real)
{
if 0.0 <= y {
N_implicitDecreases(x, y - 1.0);
} else if 0.0 <= x {
N_implicitDecreases(x - 1.0, 300.0);
}
}
method P(x: real)
decreases x;
{
if 0.0 <= x {
P(x - 0.5); // error: don't descease enough
}
}
method Q(x: real)
decreases 2.0 * x;
{
if 0.0 <= x {
Q(x - 0.5); // fine
}
}
method R(x: real)
decreases x;
{
R(x - 1.0); // error: no lower bound
}
method W0(N: real)
{
var i := 0.0;
while i < N
decreases N - i;
{
i := i + 1.0;
}
}
method W1(N: real)
{
var i := 0.0;
while i < N
{
i := i + 1.0;
}
}
method W2(N: real)
{
var i, n := 0.0, N;
while i < n
decreases n - i;
{
if * {
i := i + 1.0;
} else {
n := n - 1.0;
}
}
}
method W3(N: real)
{
var i, n := 0.0, N;
while i < n
{
if * {
i := i + 1.0;
} else {
n := n - 1.0;
}
}
}
method W4(N: real)
{
var i, n := 0.0, N;
while i != n
decreases if i < n then n - i else i - n; // absolute value
{
if i < n {
i := i + 1.0;
if n < i { break; }
} else {
n := n + 1.0;
if i < n { break; }
}
}
}
method W5(N: real)
{
var i, n := 0.0, N;
while i != n
{
if i < n {
i := i + 1.0;
if n < i { break; }
} else {
n := n + 1.0;
if i < n { break; }
}
}
}
method Test_AbsInt0()
{
var a, i := 0.3, 0;
while i < 10
invariant a == 0.3 + 0.5 * real(i);
{
a, i := a + 0.5, i + 1;
}
assert a == 5.3;
assert a < 5.9;
assert 0.59 <= a;
assert a < 0.62; // error
}
method Test_AbsInt1()
{
var a, i := 0.3, 0.0;
while i < 10.0
invariant i <= 10.0 && i == real(i.Trunc);
invariant a == 0.3 + 0.5 * i;
{
a, i := a + 0.5, i + 1.0;
}
assert a == 5.3;
assert a < 5.9;
assert 0.59 <= a;
assert a < 0.62; // error
}
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