考虑一个确定二次方程的根的性质的问题，其中输入是3个变量(a，b，c)，并且它们的值可能来自区间[0，100]。根据变量的值，输出可能是以下之一：
- 不是二次方程式
- 真正的根源
- 虚幻的根源
- 平等的根
我们的目标是设计边界值测试用例。
边界值分析是一种软件测试技术，其中的测试被设计为包括范围内边界值的代表。边界值分析共有4 * n + 1个不同的测试用例，其中n是问题中的变量数。
在这里，我们必须考虑所有三个变量，并设计所有不同的可能的测试用例。我们总共有13个测试用例，其中n = 3。
- 二次方程的类型为：ax 2 + bx + c = 0
- 如果(b 2 – 4ac)> 0，则根是实数
- 如果(b 2 – 4ac)<0，则根是虚数
- 如果(b 2 – 4ac)= 0，则根相等
- 如果a = 0，则方程不是二次方程
我们如何设计测试用例?
对于每个变量，我们考虑以下5种情况：
- 分钟= 0
- 一分钟+1 = 1
- 名义= 50
- 最大值-1 = 99
- 最大值= 100
当我们考虑变量的这5种情况时，其余变量具有标称值，例如在上述情况下，“ a”的值在0到100之间变化时，“ b”和“ c”的值将作为标称值或平均值。类似地，当变量“ b”的值从0变为100时，“ a”和“ c”的值将是标称值或平均值，即50。
边界值分析中二次方程的根的性质可能的测试用例可以是：
下面是验证上面表格中考虑的测试用例的程序。该程序采用用户定义的输入，以便您可以检查上述任何测试用例。
C++
// C++ program to check the nature of the roots
#include
using namespace std;
// BVA for nature of roots of a quadratic equation
void nature_of_roots(int a, int b, int c)
{
// If a = 0, D/2a will yield exception
// Hence it is not a valid Quadratic Equation
if (a == 0) {
cout << "Not a Quadratic Equation"
<< endl;
return;
}
int D = b * b - 4 * a * c;
// If D > 0, it will be Real Roots
if (D > 0) {
cout << "Real Roots" << endl;
}
// If D == 0, it will be Equal Roots
else if (D == 0) {
cout << "Equal Roots" << endl;
}
// If D < 0, it will be Imaginary Roots
else {
cout << "Imaginary Roots" << endl;
}
}
// Function to check for all testcases
void checkForAllTestCase()
{
cout << "Testcase"
<< "\ta\tb\tc\tActual Output"
<< endl;
cout << endl;
int a, b, c;
int testcase = 1;
while (testcase <= 13) {
if (testcase == 1) {
a = 0;
b = 50;
c = 50;
}
else if (testcase == 2) {
a = 1;
b = 50;
c = 50;
}
else if (testcase == 3) {
a = 50;
b = 50;
c = 50;
}
else if (testcase == 4) {
a = 99;
b = 50;
c = 50;
}
else if (testcase == 5) {
a = 100;
b = 50;
c = 50;
}
else if (testcase == 6) {
a = 50;
b = 0;
c = 50;
}
else if (testcase == 7) {
a = 50;
b = 1;
c = 50;
}
else if (testcase == 8) {
a = 50;
b = 99;
c = 50;
}
else if (testcase == 9) {
a = 50;
b = 100;
c = 50;
}
else if (testcase == 10) {
a = 50;
b = 50;
c = 0;
}
else if (testcase == 11) {
a = 50;
b = 50;
c = 1;
}
else if (testcase == 12) {
a = 50;
b = 50;
c = 99;
}
else if (testcase == 13) {
a = 50;
b = 50;
c = 100;
}
cout << "\t" << testcase << "\t"
<< a << "\t" << b << "\t"
<< c << "\t";
nature_of_roots(a, b, c);
cout << endl;
testcase++;
}
}
// Driver Code
int main()
{
checkForAllTestCase();
return 0;
} Java
// Java program to check the nature of the roots
import java.util.*;
class GFG
{
// BVA for nature of roots of a quadratic equation
static void nature_of_roots(int a, int b, int c)
{
// If a = 0, D/2a will yield exception
// Hence it is not a valid Quadratic Equation
if (a == 0)
{
System.out.print("Not a Quadratic Equation"
+"\n");
return;
}
int D = b * b - 4 * a * c;
// If D > 0, it will be Real Roots
if (D > 0) {
System.out.print("Real Roots" +"\n");
}
// If D == 0, it will be Equal Roots
else if (D == 0) {
System.out.print("Equal Roots" +"\n");
}
// If D < 0, it will be Imaginary Roots
else {
System.out.print("Imaginary Roots" +"\n");
}
}
// Function to check for all testcases
static void checkForAllTestCase()
{
System.out.print("Testcase"
+ "\ta\tb\tc\tActual Output"
+"\n");
System.out.println();
int a, b, c;
a = b = c = 0;
int testcase = 1;
while (testcase <= 13) {
if (testcase == 1) {
a = 0;
b = 50;
c = 50;
}
else if (testcase == 2) {
a = 1;
b = 50;
c = 50;
}
else if (testcase == 3) {
a = 50;
b = 50;
c = 50;
}
else if (testcase == 4) {
a = 99;
b = 50;
c = 50;
}
else if (testcase == 5) {
a = 100;
b = 50;
c = 50;
}
else if (testcase == 6) {
a = 50;
b = 0;
c = 50;
}
else if (testcase == 7) {
a = 50;
b = 1;
c = 50;
}
else if (testcase == 8) {
a = 50;
b = 99;
c = 50;
}
else if (testcase == 9) {
a = 50;
b = 100;
c = 50;
}
else if (testcase == 10) {
a = 50;
b = 50;
c = 0;
}
else if (testcase == 11) {
a = 50;
b = 50;
c = 1;
}
else if (testcase == 12) {
a = 50;
b = 50;
c = 99;
}
else if (testcase == 13) {
a = 50;
b = 50;
c = 100;
}
System.out.print("\t" + testcase+ "\t"
+ a+ "\t" + b+ "\t"
+ c+ "\t");
nature_of_roots(a, b, c);
System.out.println();
testcase++;
}
}
// Driver Code
public static void main(String[] args)
{
checkForAllTestCase();
}
}
// This code is contributed by 29AjayKumarPython3
# Python3 program to check the nature of the roots
# BVA for nature of roots of a quadratic equation
def nature_of_roots(a, b, c):
# If a = 0, D/2a will yield exception
# Hence it is not a valid Quadratic Equation
if (a == 0):
print("Not a Quadratic Equation");
return;
D = b * b - 4 * a * c;
# If D > 0, it will be Real Roots
if (D > 0):
print("Real Roots");
# If D == 0, it will be Equal Roots
elif(D == 0):
print("Equal Roots");
# If D < 0, it will be Imaginary Roots
else:
print("Imaginary Roots");
# Function to check for all testcases
def checkForAllTestCase():
print("Testcase\ta\tb\tc\tActual Output");
print();
a = b = c = 0;
testcase = 1;
while (testcase <= 13):
if (testcase == 1):
a = 0;
b = 50;
c = 50;
elif(testcase == 2):
a = 1;
b = 50;
c = 50;
elif(testcase == 3):
a = 50;
b = 50;
c = 50;
elif(testcase == 4):
a = 99;
b = 50;
c = 50;
elif(testcase == 5):
a = 100;
b = 50;
c = 50;
elif(testcase == 6):
a = 50;
b = 0;
c = 50;
elif(testcase == 7):
a = 50;
b = 1;
c = 50;
elif(testcase == 8):
a = 50;
b = 99;
c = 50;
elif(testcase == 9):
a = 50;
b = 100;
c = 50;
elif(testcase == 10):
a = 50;
b = 50;
c = 0;
elif(testcase == 11):
a = 50;
b = 50;
c = 1;
elif(testcase == 12):
a = 50;
b = 50;
c = 99;
elif(testcase == 13):
a = 50;
b = 50;
c = 100;
print("\t" , testcase , "\t" , a , "\t" , b , "\t" , c , "\t", end="");
nature_of_roots(a, b, c);
print();
testcase += 1;
# Driver Code
if __name__ == '__main__':
checkForAllTestCase();
# This code is contributed by 29AjayKumarC#
// C# program to check the nature of the roots
using System;
class GFG
{
// BVA for nature of roots of a quadratic equation
static void nature_of_roots(int a, int b, int c)
{
// If a = 0, D/2a will yield exception
// Hence it is not a valid Quadratic Equation
if (a == 0)
{
Console.Write("Not a Quadratic Equation"
+"\n");
return;
}
int D = b * b - 4 * a * c;
// If D > 0, it will be Real Roots
if (D > 0) {
Console.Write("Real Roots" +"\n");
}
// If D == 0, it will be Equal Roots
else if (D == 0) {
Console.Write("Equal Roots" +"\n");
}
// If D < 0, it will be Imaginary Roots
else {
Console.Write("Imaginary Roots" +"\n");
}
}
// Function to check for all testcases
static void checkForAllTestCase()
{
Console.Write("Testcase"
+ "\ta\tb\tc\tActual Output"
+"\n");
Console.WriteLine();
int a, b, c;
a = b = c = 0;
int testcase = 1;
while (testcase <= 13) {
if (testcase == 1) {
a = 0;
b = 50;
c = 50;
}
else if (testcase == 2) {
a = 1;
b = 50;
c = 50;
}
else if (testcase == 3) {
a = 50;
b = 50;
c = 50;
}
else if (testcase == 4) {
a = 99;
b = 50;
c = 50;
}
else if (testcase == 5) {
a = 100;
b = 50;
c = 50;
}
else if (testcase == 6) {
a = 50;
b = 0;
c = 50;
}
else if (testcase == 7) {
a = 50;
b = 1;
c = 50;
}
else if (testcase == 8) {
a = 50;
b = 99;
c = 50;
}
else if (testcase == 9) {
a = 50;
b = 100;
c = 50;
}
else if (testcase == 10) {
a = 50;
b = 50;
c = 0;
}
else if (testcase == 11) {
a = 50;
b = 50;
c = 1;
}
else if (testcase == 12) {
a = 50;
b = 50;
c = 99;
}
else if (testcase == 13) {
a = 50;
b = 50;
c = 100;
}
Console.Write("\t" + testcase+ "\t"
+ a+ "\t" + b+ "\t"
+ c+ "\t");
nature_of_roots(a, b, c);
Console.WriteLine();
testcase++;
}
}
// Driver Code
public static void Main(String[] args)
{
checkForAllTestCase();
}
}
// This code is contributed by 29AjayKumar输出：
Testcase a b c Actual Output
1 0 50 50 Not a Quadratic Equation
2 1 50 50 Real Roots
3 50 50 50 Imaginary Roots
4 99 50 50 Imaginary Roots
5 100 50 50 Imaginary Roots
6 50 0 50 Imaginary Roots
7 50 1 50 Imaginary Roots
8 50 99 50 Imaginary Roots
9 50 100 50 Equal Roots
10 50 50 0 Real Roots
11 50 50 1 Real Roots
12 50 50 99 Imaginary Roots
13 50 50 100 Imaginary Roots