将字符串分配给int [英] assigning string to int
问题描述
大家好，
我想知道是否有一种简单的方法可以将字符串分配给int。
I有一个结构，如：
struct Values {
int a;
int b;
}
我从文件中读取了2个字符串：
string x =" 12";
string y =" 10";
现在我想做这样的事情：
值val;
val.a = x;
val.b = y;
当然有不匹配的情况..如何解决？有一个简单的方法吗？
Thanx求救！
Ben
< blockquote>
" Ben" < CR ********* @ yahoo.com>在消息中写道
news：d9 ************************** @ posting.google.c om ...
大家好，
我想知道是否有一种简单的方法可以将字符串分配给int。
不，这两种类型不是兼容。然而
（就像它看起来你真的在问，是的
你可以转换
整数的文字表示（即一个数字字符序列）
一个整数类型。）
我有一个结构如：
struct values {
int a;
int b;
}
我从文件中读取了2个字符串：
string x =" 12";
string y =" 10";
现在我想做这样的事情：
值val;
val.a = x;
val .b = y;
当然有不匹配...我该如何解决？有一个简单的方法吗？
有几种方法，简单是一个意见问题。
然后还有一些关于更好的意见。
一种方法是使用字符串流
（你需要#include< ; sstream>
使用一个）：
std :: istringstream iss（x +'''+ y）;
iss>> val.a>> val.b;
对于（imo）更灵活，健壮的方法，查看
''strtol（）''函数，由< cstdlib>宣布
-Mike
Ben写道：大家好，
我想知道是否有一种简单的方法可以将字符串分配给
int。
我有一个结构如：
struct values {
int a;
int b;
}
我有2个字符串，我从文件中读取：
string x =" 12";
string y =" 10"
现在我想做这样的事情：
值val;
val.a = x;
val.b = y;
当然有不匹配的问题..如何解决？有没有简单的方法？
Thanx求助！
Ben
模板< typename T，typename TCHAR>
T fromstring（const std :: basic_string< TCHAR>& s）
{
std :: basic_istringstream< TCHAR，std :: char_traits< TCHAR> ;，
std :: allocator< TCHAR> > iss（s）;
T x;
iss>> x;
if（！iss）
throw std :: invalid_argument（" Bad argument！"）;
return x; < br $>
}
模板< typename T，typename TCHAR>
std :: basic_string< TCHAR> tostring（const T& x）
{
std :: basic_ostringstream< TCHAR，std :: char_traits< TCHAR>，
std ::分配器< TCHAR> > oss;
oss<< x;
if（！oss）
throw std :: invalid_argument（" Bad argument！"）;
return oss.str （）;
}
val.a = fromstring< int，char>（x）;
val.b = fromstring< int，char>（y）;
fromstring（）可以类似的方式使用。
- Pete
Petec写道：
< snip>
模板< typename T，typename TCHAR>
std :: basic_string< TCHAR> tostring（const T& x）
{
std :: basic_ostringstream< TCHAR，std :: char_traits< TCHAR>，
std :: allocator< TCHAR> > oss;
oss<< x;
if（！oss）
throw std :: invalid_argument（" Bad argument！"）;
return oss.str（）;
}
val.a = fromstring< int，char>（x）;
val.b = fromstring< int，char>（y）;
fromstring（）可以使用以类似的方式。
对不起，我的意思是tostring<>（）可以以类似的方式使用。 :)
- 皮特
Hi all,
I would like to know if there is an easy way to assign a string to an int.
I have a struct such as:
struct Values {
int a;
int b;
}
I have 2 strings that i read from a file:
string x = "12";
string y = "10";
Now I''d like to do something like this:
Values val;
val.a = x;
val.b = y;
There is of course a mis-match.. How do I fix it? Is there an easy way?
Thanx for help!
Ben
"Ben" <cr*********@yahoo.com> wrote in message
news:d9**************************@posting.google.c om...Hi all,
I would like to know if there is an easy way to assign a string to an int.
No, those two types are not ''compatible''. However
(as is what it appears you''re really asking, yes
you can convert the textual representation of an
integer (i.e. a sequence of digit characters) to
an integer type.)
I have a struct such as:
struct Values {
int a;
int b;
}
I have 2 strings that i read from a file:
string x = "12";
string y = "10";
Now I''d like to do something like this:
Values val;
val.a = x;
val.b = y;
There is of course a mis-match.. How do I fix it? Is there an easy way?
There are a few ways, which is ''easy'' is a matter of opinion.
Then there are also opinions about which is ''better''.
One way is to use a stringstream
(you''ll need to #include <sstream>
to use one):
std::istringstream iss(x + '' '' + y);
iss >> val.a >> val.b;
For a (imo) more flexible, ''robust'' method, look up the
''strtol()'' function, declared by <cstdlib>
-Mike
Ben wrote:Hi all,
I would like to know if there is an easy way to assign a string to an
int.
I have a struct such as:
struct Values {
int a;
int b;
}
I have 2 strings that i read from a file:
string x = "12";
string y = "10";
Now I''d like to do something like this:
Values val;
val.a = x;
val.b = y;
There is of course a mis-match.. How do I fix it? Is there an easy
way?
Thanx for help!
Ben
template<typename T, typename TCHAR>
T fromstring(const std::basic_string<TCHAR>& s)
{
std::basic_istringstream<TCHAR, std::char_traits<TCHAR>,
std::allocator<TCHAR> > iss(s);
T x;
iss >> x;
if(!iss)
throw std::invalid_argument("Bad argument!");
return x;
}
template<typename T, typename TCHAR>
std::basic_string<TCHAR> tostring(const T& x)
{
std::basic_ostringstream<TCHAR, std::char_traits<TCHAR>,
std::allocator<TCHAR> > oss;
oss << x;
if(!oss)
throw std::invalid_argument("Bad argument!");
return oss.str();
}
val.a = fromstring<int, char>(x);
val.b = fromstring<int, char>(y);
fromstring() can be used in a similar way.
- Pete
Petec wrote:
<snip>
template<typename T, typename TCHAR>
std::basic_string<TCHAR> tostring(const T& x)
{
std::basic_ostringstream<TCHAR, std::char_traits<TCHAR>,
std::allocator<TCHAR> > oss;
oss << x;
if(!oss)
throw std::invalid_argument("Bad argument!");
return oss.str();
}
val.a = fromstring<int, char>(x);
val.b = fromstring<int, char>(y);
fromstring() can be used in a similar way.
Sorry, I meant tostring<>() can be used in a similar way. :)
- Pete
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