实验一，现代C++编程初体验
一、实验目的
体验C++的标准库，算法库用法。数据表示，分支循环，函数和标准库等，编程解决简单基础问题。
二、实验准备
第二章C++语言简单设计
第三章函数
第九章 函数模板
三、实验内容
1. 实验任务1
代码：
1 #include<iostream> 2 #include<string> 3 #include<vector> 4 #include<algorithm> 5 6 using namespace std; 7 8 template <typename T> 9 void output (const T &c); 10 void test1(); 11 void test2(); 12 void test3(); 13 14 int main(){ 15 cout <<"测试1：\n" ; 16 test1(); 17 18 cout <<"\n测试2：\n"; 19 test2(); 20 21 cout <<"\n测试3：\n"; 22 test3(); 23 24 25 } 26 template <typename T> 27 void output(const T &c){ 28 for (auto &i:c) 29 cout << i << " "; 30 cout <<endl; 31 32 } 33 void test1(){ 34 string s0{"0123456789"}; 35 cout <<"s0 = "<<s0<<endl; 36 37 string s1{s0}; 38 reverse(s1.begin(), s1.end()); 39 cout <<"s1 = "<<s1<<endl; 40 41 string s2{s0}; 42 reverse_copy(s0.begin(),s0.end(),s2.begin()); 43 44 cout << "s2 = "<<s1<<endl; 45 } 46 47 void test2() 48 { 49 vector <int> v0{2,0,4,9}; 50 cout<<"v0: "; 51 output(v0); 52 53 vector<int> v1{v0}; 54 reverse(v1.begin(),v1.end()); 55 cout <<"v1: "; 56 output(v1); 57 58 vector<int> v2{v0}; 59 reverse_copy(v0.begin(),v0.end(),v2.begin()); 60 cout<<"v2: "; 61 output(v2); 62 } 63 64 void test3(){ 65 vector<int> v0{0,1,2,3,4,5,6,7,8,9}; 66 cout<<"v0: " ; 67 output(v0); 68 69 vector<int> v1{v0}; 70 rotate(v1.begin(),v1.begin()+1,v1.end()); 71 cout << "v1: "; 72 output(v1); 73 74 vector<int>v2{v0}; 75 rotate(v2.begin(),v2.begin()+2,v2.end()); 76 cout<<"v2: "; 77 output(v2); 78 79 vector<int> v3{v0}; 80 rotate(v3.begin(),v3.end()-1,v3.end()); 81 cout <<"v3: " ; 82 output(v3); 83 84 vector<int>v4{v0}; 85 rotate (v4.begin(),v4.end()-2,v4.end( )); 86 cout<<"v4: "; 87 output(v4); 88 89 } 90 91 92
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问题回答：
2. 实验任务2
代码：
1 #include<iostream> 2 #include<vector> 3 #include<string> 4 #include<algorithm> 5 #include<numeric> 6 #include<iomanip> 7 8 9 using namespace std; 10 11 template < typename T> 12 void output (const T&c); 13 14 15 int rand_int_100(); 16 void test1(); 17 void test2(); 18 19 int main(){ 20 cout << "测试1：\n"; 21 test1(); 22 23 cout<<"\n测试2: \n"; 24 test2(); 25 26 } 27 28 template <typename T> 29 void output (const T&c){ 30 31 for (auto &i:c) 32 cout<< i << " "; 33 cout<<endl; 34 } 35 36 37 int rand_int_100(){ 38 39 return rand()%101; 40 41 } 42 43 void test1(){ 44 vector<int> v0(10); 45 generate(v0.begin(),v0.end(),rand_int_100); 46 cout << "v0: "; 47 output(v0); 48 vector<int> v1{v0}; 49 sort(v1.begin(),v1.end()); 50 51 cout << "v1: "; 52 output(v1); 53 54 vector <int> v2{v0}; 55 sort(v2.begin()+1,v2.end()-1); 56 57 cout << "v2: "; 58 output(v2); 59 60 } 61 62 void test2(){ 63 64 65 vector <int> v0(10); 66 generate(v0.begin(),v0.end(),rand_int_100); 67 cout<< "v0: "; 68 output(v0); 69 70 auto iter1 = min_element (v0.begin(),v0.end()); 71 cout<<"最小值："<< *iter1<<endl; 72 73 auto iter2 = max_element(v0.begin(),v0.end()); 74 cout<<"最大值："<< *iter2<<endl; 75 76 auto ans = minmax_element(v0.begin(),v0.end()); 77 cout<<"最小值："<< *(ans.first)<<endl; 78 cout<<"最大值："<<*(ans.second)<<endl; 79 double avg1= accumulate (v0.begin(),v0.end(),0)/v0.size(); 80 cout<<"均值："<<fixed<<setprecision(2)<<avg1<<endl; 81 82 cout << endl; 83 vector <int> v1{v0}; 84 cout<<"v0: "; 85 output(v0); 86 sort(v1.begin(),v1.end()); 87 double avg2 = accumulate (v1.begin()+1,v1.end()-1,0)/(v1.size()-2); 88 cout<<"去掉最大值、最小值之后，均值："<<avg2<<endl; 89 90 } 91
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问题回答：
3. 实验任务3
代码：
1 #include<iostream> 2 #include<string> 3 #include<algorithm> 4 #include<vector> 5 6 7 8 bool is_palindrome(const std::string &s); 9 10 11 int main(){ 12 using namespace std; 13 string s; 14 15 while (cin>>s ){ 16 cout<< boolalpha << is_palindrome(s) << endl; 17 } 18 19 return 0; 20 21 } 22 bool is_palindrome(const std::string &s){ 23 24 std::string s1{s}; 25 std::reverse(s1.begin(),s1.end()); 26 return s1==s; 27 28 29 }
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4. 实验任务4
代码：
1 #include<iostream> 2 #include<string> 3 #include<algorithm> 4 5 using namespace std; 6 7 string dec2n(int x,int n=2){ 8 9 string result; 10 11 if (n==2||n==8){ 12 while (x>0) { 13 int y=x%n; 14 result+=(y+'0'); 15 x/=n; 16 } 17 reverse(result.begin(),result.end()); 18 return result; 19 } 20 21 22 if( n==16){ 23 24 while(x>0){ 25 int z=x%16; 26 if(z<10) { 27 result+='0'+z; 28 } 29 else{ 30 result+='A'+(z-10); 31 } 32 x/=16; 33 } 34 reverse(result.begin(),result.end()); 35 return result; 36 } 37 38 39 } 40 41 42 43 44 45 int main(){ 46 47 using namespace std; 48 49 int x; 50 while (cin >>x){ 51 52 cout<<"十进制："<< x <<endl; 53 cout <<"二进制："<< dec2n(x)<<endl; 54 cout <<"八进制："<< dec2n(x,8)<<endl; 55 cout <<"十六进制："<< dec2n(x,16) <<endl<<endl; 56 } 57 return 0; 58 }
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问题回答：
5. 实验任务5
代码：
1 #include<iostream> 2 #include<string> 3 #include<iomanip> 4 using namespace std; 5 int main(){ 6 7 8 9 10 char a; 11 cout<<setw(2)<<' '; 12 for (int i =0;i< 26;i++) 13 { 14 a='a'+i; 15 cout <<setw(2) <<a; 16 17 } 18 cout << endl; 19 20 for (int i=1;i<27;i++) 21 { 22 cout <<setw(2)<<i; 23 for (int j=0;j<26;j++) 24 { 25 int t=(i+j)%26; 26 a='A'+t; 27 cout<<setw(2)<<a; 28 } 29 cout<<endl; 30 } 31 32 33 34 35 36 37 return 0 ; 38 }
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问题回答：
6. 实验任务6
代码：
1 #include<iostream> 2 #include<cstdlib> 3 #include<ctime> 4 #include<iomanip> 5 6 using namespace std; 7 8 int getrandomnum(int min, int max) 9 { 10 return rand ()%(max-min +1)+min; 11 12 } 13 14 int calculate(int a, int b, char operation) 15 { 16 17 switch (operation) 18 { 19 case '+': 20 return a+b; 21 case '-': 22 return a-b; 23 case '*': 24 return a*b; 25 case '/': 26 return a/b; 27 default: 28 return 0; 29 } 30 } 31 int main() 32 { 33 srand(static_cast<unsigned int > (time(0))); 34 35 const int shuliang=10; 36 int rightanswers=0; 37 38 int a,b,answer; 39 40 char operation; 41 42 for (int i=0;i<shuliang;++i) 43 { 44 45 46 int num1=getrandomnum(1,4); 47 if (num1==1) 48 { 49 operation='+'; 50 a=getrandomnum(1,10); 51 b=getrandomnum(1,10); 52 53 } 54 else if(num1==2) 55 { 56 operation='-'; 57 a=getrandomnum(2,10); 58 b=getrandomnum(1,a-1); 59 60 } 61 else if (num1==3) 62 { 63 operation='*'; 64 a=getrandomnum(1,10); 65 b=getrandomnum(1,10); 66 } 67 else if(num1==4) 68 { 69 operation='/'; 70 b=getrandomnum(1,10); 71 a=b*getrandomnum(1,1); 72 } 73 cout<<setw(2)<<a<<setw(2)<<operation<<setw(2)<<b<<setw(2)<<"="; 74 75 76 cin>>answer; 77 78 79 80 int rightanswer= calculate(a,b,operation); 81 if (answer==rightanswer) 82 { 83 rightanswers++; 84 85 } 86 } 87 double accuracy=(static_cast<double>(rightanswers)/shuliang)*100; 88 cout<<"正确率： "<<fixed<< setprecision(2)<<accuracy<<"%"<<endl; 89 90 return 0; 91 }
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