使用预处理器进行调试

一、预处理指令

问题：输入一些WORD,判断有没有首字母大写的两个相同的词

 1 #include<iostream>
 2 #include<string>
 3 
 4 using namespace std;
 5 
 6 int main()
 7 {
 8     string currWord, preWord;
 9     cout << "Enter some words:(ctrl+z to end)" << endl;
10     while (cin >> currWord)
11     {
12 #ifndef NDEBUG
13         cout << endl << "调试：" << currWord << endl;  //这是调试用的
14 #endif
15         if (!isupper(currWord[0]))
16             continue;
17         if (currWord == preWord)
18             break;
19         else preWord = currWord;
20     }
21     if (currWord == preWord&&!currWord.empty())
22     {
23         cout << "The repeated word:" << currWord << endl;
24     }
25     else
26         cout << "没有重复的！" << endl;
27     system("pause");
28 }

关闭预处理：

解决资源方案--demo--右键“属性”--c++--命令行----附加选项：/DNDEBUG

结果：

二、预处理常量

 1 #include<iostream>
 2 #include<string>
 3 
 4 using namespace std;
 5 
 6 int main()
 7 {
 8     cout << "文件：" << __FILE__ << endl<<"行：" << __LINE__ << endl<<"日期：" << __DATE__ << endl<<"时间：" << __TIME__ << endl;
 9     system("pause");
10 }

三、assert断言

 1 #include<iostream>
 2 #include<assert.h>
 3 
 4 using namespace std;
 5 
 6 int add(int x, int y)
 7 {
 8     return x * y;
 9 }
10 int main()
11 {
12     int result;
13     result = add(1, 2);
14     assert(result == 3);
15     cout << result << endl;
16     system("pause");
17 }

断言也用来调试，与预定义一样，受附加选项/DNDEBUG控制