Esempio n. 1
0
func TestStack(t *testing.T) {
	count := 1
	var aStack stack.Stack
	assertTrue(t, aStack.Len() == 0, "expected empty Stack", count) // 1
	count++
	assertTrue(t, aStack.Cap() == 0, "expected empty Stack", count) // 2
	count++
	assertTrue(t, aStack.IsEmpty(), "expected empty Stack", count) // 3
	count++
	value, err := aStack.Pop()
	assertTrue(t, value == nil, "expected nil value", count) // 4
	count++
	assertTrue(t, err != nil, "expected error", count) // 5
	count++
	value1, err := aStack.Top()
	assertTrue(t, value1 == nil, "expected nil value", count) // 6
	count++
	assertTrue(t, err != nil, "expected error", count) // 7
	count++
	aStack.Push(1)
	aStack.Push(2)
	aStack.Push("three")
	assertTrue(t, aStack.Len() == 3, "expected nonempty Stack", count) // 8
	count++
	assertTrue(t, aStack.IsEmpty() == false, "expected nonempty Stack",
		count) // 9
	count++
	value2, err := aStack.Pop()
	assertEqualString(t, value2.(string), "three", "unexpected text",
		count) // 10
	count++
	assertTrue(t, err == nil, "no error expected", count) // 11
	count++
	value3, err := aStack.Top()
	assertTrue(t, value3 == 2, "unexpected number", count) // 12
	count++
	assertTrue(t, err == nil, "no error expected", count) // 13
	count++
	aStack.Pop()
	assertTrue(t, aStack.Len() == 1, "expected nonempty Stack", count) //14
	count++
	assertTrue(t, aStack.IsEmpty() == false, "expected nonempty Stack",
		count) // 15
	count++
	value4, err := aStack.Pop()
	assertTrue(t, value4 == 1, "unexpected number", count) // 16
	count++
	assertTrue(t, err == nil, "no error expected", count) // 17
	count++
	assertTrue(t, aStack.Len() == 0, "expected empty Stack", count) // 18
	count++
	assertTrue(t, aStack.IsEmpty(), "expected empty Stack", count) // 19
	count++
}
Esempio n. 2
0
// convert2postfix converts an infix expression to postfix
func convert2postfix(tokens []string) []string {
	var stack stack.Stack
	var result []string
	for _, token := range tokens {

		if isOperator(token) {

		OPERATOR:
			for {
				top, err := stack.Top()
				if err == nil && top != "(" {
					if opGTE(top.(string), token) {
						pop, _ := stack.Pop()
						result = append(result, pop.(string))
					} else {
						break OPERATOR
					}
				}
				break OPERATOR
			}
			stack.Push(token)

		} else if token == "(" {
			stack.Push(token)

		} else if token == ")" {
		PAREN:
			for {
				top, err := stack.Top()
				if err == nil && top != "(" {
					pop, _ := stack.Pop()
					result = append(result, pop.(string))
				} else {
					stack.Pop() // pop off "("
					break PAREN
				}
			}

		} else if isOperand(token) {
			result = append(result, token)
		}

	}

	for !stack.IsEmpty() {
		pop, _ := stack.Pop()
		result = append(result, pop.(string))
	}

	return result
}