c++primer第五版课后练习答案（第三章）

chapter1_3.2

#include "stdafx.h"#include  "string"#include "iostream"using namespace std;int _tmain(int argc, _TCHAR* argv[]){string line;while (getline(cin, line)){cout << line<<endl ;}return 0;}/*int _tmain(int argc, _TCHAR* argv[]){string word;while (cin>>word){cout << word<<endl;}return 0;}*/

chapter1_3.6

#include "stdafx.h"#includ<pre name="code" class="cpp">#include "stdafx.h"#include "string"#include "iostream"using namespace std;int _tmain(int argc, _TCHAR* argv[]){string line;getline(cin, line);for (auto &c : line){if (!ispunct(c)){cout << c;}}cout << endl;return 0;}

chapter1_3.7

#include "stdafx.h"#include "iostream"#include "string"using namespace std;int _tmain(int argc, _TCHAR* argv[]){string s("some string");cout << s << endl;for (char &c : s)   //为什么此处c必须是引用，才能改变字符的值  {if (c!=' ')c = 'X';}cout << s << endl;return 0;}

//运行结果是同样可以实现改变字符功能

chapter1_3.8

#include "stdafx.h"#include "iostream"#include "string"using namespace std;int _tmain(int argc, _TCHAR* argv[]){string s("some string");cout << s << endl;decltype(s.size()) i = 0;while (i < s.size){if (s[i] != ' '){s[i] = 'X';}i++;}/*for (decltype(s.size()) i = 0; i < s.size(); i++){if (s[i] != ' '){s[i] = 'X';}}*/cout << s << endl;return 0;}

chapter1_3.10

#include "stdafx.h"#include "string"#include "iostream"using namespace std;int _tmain(int argc, _TCHAR* argv[]){string line;getline(cin, line);for (auto &c : line){if (!ispunct(c)){cout << c;}}cout << endl;return 0;}

chapter1_3.14

#include "stdafx.h"#include <vector>#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<int> ivec;int i;while (cin >> i){ivec.push_back(i);}return 0;}

chapter1_3.15

#include "stdafx.h"#include <vector>#include <iostream>#include <string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){string word;vector<string> ivec;while (cin >> word)ivec.push_back(word);return 0;}

chapter1_3.15

#include "stdafx.h"#include <vector>#include <iostream>#include <string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<int> v1;//空vector对象，无元素；vector<int> v2(10);//10个元素，初始值为0；vector<int> v3(10, 42);//十个水元素，初始值均为42；vector<int> v4{ 10 }; //一个元素，值为10；vector<int> v5{ 10, 42 };//两个元素，分别为10、42；vector<string> v6{ 10 };//十个默认初始化的元素vector<string> v7{ 10, "hi" };//十个初始化值为“hi”的元素return 0;}

chapter1_3.17

#include "stdafx.h"#include <vector>#include <iostream>#include <string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){string word;vector <string> ivec;while (cin>>word){ivec.push_back(word);}for (vector<string>::size_type ix = 0; ix != ivec.size(); ++ix){for (string::size_type index = 0; index != ivec[ix].size(); ++index){if (islower(ivec[ix][index])){ivec[ix][index] = toupper(ivec[ix][index]);}}}for (string::size_type i = 0; i<ivec.size();++i){cout <<ivec[i]<<endl;}return 0;}

chapter1_3.20

#include "stdafx.h"#include <vector>#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<int> ivec;int i;while (cin >> i){ivec.push_back(i);}/*     输出每对相邻整数的和for (int i = 0; i < ivec.size()-1; ){cout << ivec[i] + ivec[i + 1]<<endl;i = i + 1;}*///依次输出首尾整数的和for (int i = 0, j = ivec.size() - 1; i<ivec.size()/2; i++,j--){cout << ivec[i] + ivec[j] << endl;}return 0;}

chapter1_3.22

#include "stdafx.h"#include <iostream>#include <vector>#include <string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){string text("somg string");for (auto it = text.begin();it != text.end()&&!isspace(*it); ++it){*it = toupper(*it);cout << *it;}return 0;}

chapter1_3.23

#include "stdafx.h"#include <string>#include <iostream>#include <vector>#include <iomanip>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<int> ivec;int i,j=1;while (j <11){cin >> i;ivec.push_back(i);j++;}for (auto it = ivec.begin(); it != ivec.end(); ++it){*it = (*it)*2;}for (auto it = ivec.begin(); it != ivec.end(); ++it){cout << setw(6)<<*it;}return 0;}

chapter1_3.24

#include "stdafx.h"#include <vector>#include <string>#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<int> ivec;int i;while (cin >> i){ivec.push_back(i);}for (auto it = ivec.begin(); it != ivec.end(); ++it){if ((it + 1) != ivec.end())cout << (*it) + (*it + 1) << endl;}auto p = ivec.begin();auto q = ivec.end() - 1;for (int i=0;i<ivec.size()/2;++p,--q,i++)cout << *p + (*q) << endl;return 0;}

chapter1_3.25

#include "stdafx.h"#include <vector>#include <iostream>#include <iomanip>using namespace std;int _tmain(int argc, _TCHAR* argv[]){vector<unsigned> ivec;unsigned grade;while (cin >> grade){ivec.push_back(grade);}for (int n = 0; n < 11; n++){int num = 0;for (auto is = ivec.begin(); is != ivec.end(); is++){if ((*is) / 10 == n)num++;}cout << setw(4) << num;}cout << endl;return 0;}