//把邮箱地址字符串[email protected],取出其中用户名字符串打印
string getUsername(string& s)
{
int pops=s.find('@');
string username=s.substr(0, pops);
return username;
}
//大小写转换 使用标准库提供俩函数,单个字符为操作对象
string str = "asvfE GDF";
for (int i = 0; i < str.size(); i++)
{
str[i] = tolower(str[i]);
}
cout << "str:" << str << endl;
for (int i = 0; i < str.size(); i++)
{
str[i] = toupper(str[i]);
}
cout << "str:" << str << endl;
return 0;