c++ primer plus 习题答案(1)

 1 #include<iostream>
 2 #include<string>
 3 #include<cstring>
 4 char* getname(char*);
 5 
 6 struct pissza {
 7     char *pt;
 8     int diameter;
 9     int weight;
10 };
11 
12 using namespace std;
13 int main(void){
14     pissza will;
15     getname(will.pt);
16     cout << "enter a diameter\n";
17     cin >> will.diameter;
18     cout << "enter a weight\n";
19     cin >> will.weight;
20     cout << will.pt << " has a pissza " << will.diameter
21         << " m " << will.weight << " g\n";
22     cin.get(); 
23     cin.get();
24     return 0;
25 }
26 
27 char* getname(char*pt){
28     char name[20];
29     cout << "enter a name\n";
30     cin.getline(name, 20);
31     pt = new char[strlen(name) + 1];
32     strcpy(pt, name);
33     return pt;
34 }

 1 #include<iostream>
 2 #include<ctime>
 3 #include<cstdlib>
 4 
 5 int main(void){
 6     using namespace std;
 7     int i, j, count=0, sum = 0, pt[10];
 8     double mean;
 9     for (i = 0; i < 10; i++){
10         if (!(cin >> pt[i]))
11             break;
12         sum += pt[i];
13     }
14     mean = sum / i;
15     for (j = 0; j <= i; j++)
16         if (pt[j]>mean)
17             count++;
18     cout << "mean is " << mean << endl;
19     cout << "there " << count << " exceed mean\n";
20 
21     int time=10;
22     clock_t delay = time* CLOCKS_PER_SEC;
23     clock_t start = clock();
24     while (clock() - start < delay)
25         continue;    
26     
27     return 0;
28 }

 1 #include<iostream>
 2 #include<cstdlib>
 3 #include<cctype>
 4 #include<string>
 5 using namespace std;
 6 
 7 int main(){
 8     string word;
 9     int vowel = 0, con = 0, other=0;
10     while (cin >> word && word != "q"){
11         if (isalpha(word[0]))
12             switch (word[0]){
13             case ‘A‘:
14             case ‘a‘:
15                 vowel++;
16                 continue;
17             case ‘E‘:
18             case ‘e‘:
19                 vowel++;
20                 continue;
21             case ‘I‘:
22             case ‘i‘:
23                 vowel++;
24                 continue;
25             case ‘O‘:
26             case ‘o‘:
27                 vowel++;
28                 continue;
29             case ‘U‘:
30             case ‘u‘:
31                 vowel++;
32                 continue;
33             default: con++;
34         }
35         else other++;
36     }
37 
38     cout << vowel << "words beginning with vowels\n";
39     cout << con << "words beginning with consonants\n";
40     cout << other << "others\n";
41 
42     system("pause");
43     return 0;
44 }

 1 #include<iostream>
 2 #include<cstdlib>
 3 #include<cctype>
 4 #include<string>
 5 #include<fstream>
 6 using namespace std;
 7 
 8 int main(){
 9     string name;
10     cout << "enter the file name\n";
11     getline(cin, name);
12     ifstream inFile;
13     inFile.open(name);
14     if (!inFile.is_open()){
15         cout << "can‘t open the file\n";
16         exit(EXIT_FAILURE);
17     }
18     char ch;
19     int count = 0;
20     inFile >> ch;
21     while (inFile.good()){
22         count++;
23         inFile >> ch;
24     }
25     if (inFile.eof())
26         cout << "reading completed successfully\n";
27     else if (inFile.fail())
28         cout << "reading terminated by data dismatch\n";
29     if (count == 0)
30         cout << "no data processed\n";
31     else
32         cout << "count is " << count << endl;
33     inFile.close();
34     system("pause");
35     return 0;
36 }