软件工程第三次作业

求最大连续子数组和（最大子段和）

问题描述：给定n个整数（可能为负数）组成的序列a[1],a[2],a[3],…,a[n],求该序列如a[i]+a[i+1]+…+a[j]的子段和的最大值。当所给的整数均为负数时定义子段和为0，依此定义，所求的最优值为： Max{0,a[i]+a[i+1]+…+a[j]},1<=i<=j<=n
例如，当（a[1],a[2],a[3],a[4],a[5],a[6]）=(-2,11,-4,13,-5,-2)时，最大子段和为20。
-- 引用自《百度百科》

1、流程图


###2、编写程序代码 ``` #include "pch.h" #include #include #include #include using namespace std; int main() { int a[100], i, n, sum = 0, sum1 = 0; cin >> n; for (i = 0;i < n;i++) { cin >> a[i]; } for (i = 0;i < n;i++) { sum1 += a[i]; if (sum1 > sum) { sum = sum1; } else if (sum1 < 0) { sum1 = 0; } } cout << sum; return 0; } ``` ####程序代码已上传到coding.net系统中【[点此进入](https://dev.tencent.com/u/a__wang/p/qiuzuidalianxuzishuzuhe/git/blob/master/sum)】 ###3、编写单元测试 ``` #include "stdafx.h" #include "CppUnitTest.h" #include "..\最大连续子数组和\head.h"

using namespace Microsoft::VisualStudio::CppUnitTestFramework;

namespace UnitTest1
{
TEST_CLASS(UnitTest1)
{
public:

	TEST_METHOD(TestMethod1)
	{
		int n = 3;
		int a[] = { -1,-2,-4 };
		Assert::AreEqual(maxsum(n,a), 0);
	}
	TEST_METHOD(TestMethod2)
	{
		int n = 6;
		int a[] = { -2,11,-4,13,-5,-2 };
		Assert::AreEqual(maxsum(n, a), 20);
	}
	TEST_METHOD(TestMethod3)
	{
		int n = 8;
		int a[] = { 2,-3,4,-5,6,-7,-1,9 };
		Assert::AreEqual(maxsum(n, a), 9);
	}
	TEST_METHOD(TestMethod4)
	{
		int n = 10;
		int a[] = { 10,4,-100,99,3,4,-10,2,55,44};
		Assert::AreEqual(maxsum(n, a), 197);
	}
};

}

###<font color=black>4、测试结果</font>
<img src="https://img2018.cnblogs.com/blog/1644582/201904/1644582-20190417154544922-1692545548.png" width="100%" height="100%" />
####<font color=black>由图可知测试结果均正确！！！</font>