C++ Primer-第四章习题

最新推荐文章于 2025-05-03 09:23:35 发布

daxiji1295

最新推荐文章于 2025-05-03 09:23:35 发布

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文章标签： c/c++

原文链接：http://www.cnblogs.com/archerzon/p/9643206.html

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本文深入探讨了C++中的条件判断与循环控制结构，包括if语句、while循环、for循环及条件运算符的使用，展示了如何通过不同的控制结构实现数值检查、字符串处理、数组操作等功能。

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4.6　　

 1 #include <iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     cout << "Enter one number: " << endl;
 6     int checkNum;
 7     while (cin>>checkNum){
 8         if (checkNum % 2 == 1||checkNum%2==-1)
 9             cout << "奇数" << endl;
10         else if (checkNum % 2 == 0)
11             cout << "偶数" << endl;
12         else
13             cout << "0既不是奇数也不是偶数" << endl;
14     }
15     system("pause");
16     return 0;
17 }

View Code

4.10

 1 #include <iostream>
 2 #include <vector>
 3 #include <string>
 4 using namespace std;
 5 int main()
 6 {
 7     int checkNum = 42,i;
 8     while (cin >> i) {
 9         if (i == checkNum){
10             cout << "Get it!";
11             break;
12         }
13     }
14     cout << endl;
15     system("pause");
16     return 0;
17 }

View Code

4.11

 1 #include <iostream>
 2 #include <vector>
 3 #include <string>
 4 using namespace std;
 5 int main()
 6 {
 7     int a, b, c, d;
 8     cin >> a >> b >> c >> d;
 9     if (a > b&&b > c&&c > d) {
10         cout << "yes,d<c<b<a";
11     }
12     else
13         cout << "no";
14     cout << endl;
15     system("pause");
16     return 0;
17 }

View Code

P132 使用后置递增运算符输出直到遇到第一个负数

 1 #include <iostream>
 2 #include <vector>
 3 #include <string>
 4 using namespace std;
 5 int main()
 6 {
 7     vector<int> vec{ 1,2,3,4,5,6,-1,2 };
 8     auto pbeg = vec.begin();
 9     while (pbeg != vec.end() && *pbeg >= 0) {
10         cout << *pbeg++ << endl;
11     }
12     system("pause");
13     return 0;
14 }

View Code

4.17

前置运算符将对象本身作为左值返回，后置运算符则将对象原始值的副本作为右值返回。

P134

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 int main()
 5 {
 6     int grade = 59;
 7     string finalgrade = (grade < 60) ? "fail" : "pass";
 8     for (auto &c : finalgrade)
 9         cout << c << "";
10     cout << endl;
11     system("pause");
12     return 0;
13 }

View Code

P134

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 int main()
 5 {
 6     int grade;
 7     while (cin >> grade) {
 8         if (grade<=100&grade>0){
 9             string finalgrade = (grade >= 90) ? "high pass" : (grade < 60) ? "fail" : "pass";
10             for (auto &c : finalgrade) {
11                 cout << c << "";
12             }
13             cout << endl;
14         }
15     }
16     system("pause");
17     return 0;
18 }

View Code

4.21

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 int main()
 5 {
 6     vector<int> nums{ 1,2,3,4,5,6,7,8,9 };
 7     for (auto &c : nums) {
 8         int i = (c % 2 == 1) ? (c *= 2) : c;
 9         cout << c << " ";
10     }
11     cout << endl;
12     system("pause");
13     return 0;
14 }

View Code

4.22

条件运算符：

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 int main()
 5 {
 6     int grade;
 7     while (cin >> grade) {
 8         string finalgrade = (grade > 90) ? "high pass" : (grade < 60) ? "fail" : (grade < 75) ? "low pass" : "pass";
 9         for (auto &c : finalgrade) {
10             cout << c << "";
11         }
12         cout << endl;
13     }
14     system("pause");
15     return 0;
16 }

View Code

if语句：

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 int main()
 5 {
 6     int grade;
 7     while (cin >> grade) {
 8         if (grade > 90) {
 9             cout << "high pass" << endl;
10         }
11         else if (grade >= 60) {
12             if (grade < 75) {
13                 cout << "low pass" << endl;
14             }
15             else
16                 cout << "pass" << endl;
17         }
18         else
19             cout << "fail" << endl;
20     }
21     system("pause");
22     return 0;
23 }