帮我看下为何这里运算符重载失败

#include "stdafx.h"
#include <vector>
#include <deque>
#include <algorithm>
#include <iostream>
#include <ostream>
using namespace std;

class sumsqplus1
{
public :
    sumsqplus1():value(0){};
    int operator {}()
    {
        ++value; return value*value + 1;
    }
private:
    int value;
};


int main( )

{
    vector<int> int_vector(4);
    generate(int_vector.begin(),int_vector.end(),sumsqplus1{});
    for each (int elme in int_vector)
    {
        cout << elme << " " << endl;
    }
    return 0;
}这段代码重载了{},不知道为什么总是失败，要换成（）才可以成功，有那个高人知道为什么呢？
1>e:\soft\vc++\test\slt_generate\slt_generate\slt_generate.cpp(16) : error C2833: 'operator {' is not a recognized operator or type
1>e:\soft\vc++\test\slt_generate\slt_generate\slt_generate.cpp(16) : error C2059: syntax error : 'newline'
1>e:\soft\vc++\test\slt_generate\slt_generate\slt_generate.cpp(16) : error C2143: syntax error : missing ';' before '}'
1>e:\soft\vc++\test\slt_generate\slt_generate\slt_generate.cpp(16) : error C2238: unexpected token(s) preceding ';'
1>e:\soft\vc++\test\slt_generate\slt_generate\slt_generate.cpp(16) : fatal error C1903: unable to recover from previous error(s); stopping compilation

[ 本帖最后由 lsrwan 于 2010-4-21 23:29 编辑 ]