我想让下面的代码片段进行编译。但它失败了:
错误C2665:'boost :: lambda :: function_adaptor :: apply':8个重载中没有一个可以转换所有参数类型。调用bind时指定返回类型没有帮助。
知道我做错了吗?
#include <boost/lambda/lambda.hpp>
#include <boost/lambda/bind.hpp>
#include <string>
#include <map>
int main()
{
namespace bl = boost::lambda;
typedef std::map<int, std::string> types;
types keys_and_values;
keys_and_values[ 0 ] = "zero";
keys_and_values[ 1 ] = "one";
keys_and_values[ 2 ] = "Two";
std::for_each(
keys_and_values.begin(),
keys_and_values.end(),
std::cout << bl::constant("Value empty?: ") << std::boolalpha <<
bl::bind(&std::string::empty,
bl::bind(&types::value_type::second, _1)) << "\n");
return 0;
}
答案 0 :(得分:2)
使用g ++进行编译的小改动(更好的编译器的时间:-)?)
1 #include <boost/lambda/lambda.hpp>
2 #include <boost/lambda/bind.hpp>
3 #include <algorithm>
4 #include <iostream>
5 #include <string>
6 #include <map>
7
8 int main()
9 {
10
11 namespace bl = boost::lambda;
12 typedef std::map<int, std::string> types;
13 types keys_and_values;
14 keys_and_values[ 0 ] = "zero";
15 keys_and_values[ 1 ] = "one";
16 keys_and_values[ 2 ] = "Two";
17
18 std::for_each(
19 keys_and_values.begin(),
20 keys_and_values.end(),
21 std::cout << bl::constant("Value empty?: ") << std::boolalpha <<
22 bl::bind(&std::string::empty,
23 bl::bind(&types::value_type::second, bl::_1)) << "\n");
24
25
26
27
28 return 0;
29 }
通知缺少包含和bl::_1
答案 1 :(得分:1)
#include <boost/foreach.hpp>
...
#define foreach BOOST_FOREACH
...
foreach(types::value_type kv, keys_and_values)
std::cout << "Value empty?: " << std::boolalpha
<< kv.second.empty() << "\n";
...