程序清单4.8——课本69页

1 可以将string对象声明为简单变量，而不是数组

#include<iostream>
#include<string>
using namespace std;
int main()
{
char charr1[20];
char charr2[20]="jaguar";
string str1;
string str2="panther";

cout<<"Enter a kind of feline：";
cin>>charr1;
cout<<"Enter another kind of feline：";
cin>>str1;
cout<<"Here are some felines：\n";
cout<<charr1<<" "<<charr2<<" "
<<str1<<" "<<str2
<<endl;
cout<<"The third letter in "<<charr2<<" is "
<<charr2[2]<<endl;
cout<<"The third letter in "<<str2<<" is "
<<str2[2]<<endl;
system("pause");
return 0;
}

2 字符串或string对象与string对象相加，或将它们附加到string对象的末尾

 

#include<iostream>
#include<string>
using namespace std;
int main()
{
string s1="penguin";
string s2,s3;

 

cout<<"You can assign one string object to anther：s2=s1\n";
s2=s1;
cout<<"s1："<<s1<<"，s2："<<s2<<endl;
cout<<"You can assign a C-style string to a string object.\n";
cout<<"s2=\"buzzard\"\n";
s2="buzzard";
cout<<"s2："<<s2<<endl;
cout<<"You can concatenate strings：s3=s1+s2\n";
s3=s1+s2;
cout<<"s3："<<s3<<endl;
cout<<"You can append strings.\n";
s1+=s2;
cout<<"s1 += s2 yields s1 = "<<s1<<endl;
s2+="for a day";
cout<<"s2 += \" for a day\" yields s2 = "<<s2<<endl;
system("pause");
return 0;
}

3 对用于string对象的技术和用于字符数组的技术进行比较

#include<iostream>
#include<string>
#include<cstring>
using namespace std;
int main()
{
char charr1[20];
char charr2[20]="jaguar";
string str1;
string str2="panther";

str1=str2;
strcpy(charr1,charr2);

str1+="paste";
strcat(charr1,"juice");

int len1=str1.size();
int len2=strlen(charr1);

cout<<"The string "<<str1<<" contains "
<<len1<<" characters.\n";
cout<<"The string "<<charr1<<" contains "
<<len2<<" characters.\n";

system("pause");
return 0;
}

4 string类I/O

#include<iostream>
#include<string>
#include<cstring>
using namespace std;
int main()
{
char charr[20];
string str;

cout<<"Length of string in charr before input："
<<strlen(charr)<<endl;//
cout<<"Length of string in str before input："
<<str.size()<<endl;
cout<<"Enter a line of text：\n";
cin.getline(charr,20);
cout<<"you entered："<<charr<<endl;
cout<<"Enter another line of text：\n";
getline(cin,str);
cout<<"You entered："<<str<<endl;
cout<<"Length of string in charr after input："
<<strlen(charr)<<endl;
cout<<"Length of string in str after input："
<<str.size()<<endl;
system("pause");
return 0;
}