C:\Temp>type meow.cpp
#include <algorithm>
#include <iostream>
#include <ostream>
#include <vector>
using namespace std;
class Foo {
public:
explicit Foo(const int x) : m_x(x) { }
void mult(vector<vector<int>>& outer) const {
for_each(outer.begin(), outer.end(), [&](vector<int>& inner) {
for_each(inner.begin(), inner.end(), [&](int& elem) {
elem *= m_x;
});
});
}
private:
int m_x;
};
int main() {
Foo f(1000);
vector<vector<int>> v(3, vector<int>(4));
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
v[i][j] = i * 10 + j;
}
}
f.mult(v);
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
cout << v[i][j] << " ";
}
cout << endl;
}
}
C:\Temp>cl
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 17.00.40309 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
usage: cl [ option... ] filename... [ /link linkoption... ]
C:\Temp>cl /EHsc /nologo /W4 meow.cpp
meow.cpp
meow.cpp(14) : error C3494: 'this' cannot be captured in a nested lambda
meow.cpp(14) : error C2065: 'm_x' : undeclared identifier
meow.cpp(14) : error C2065: 'm_x' : undeclared identifier
C:\Temp>g++ -Wall -Wextra -std=c++0x meow.cpp -o meow.exe
C:\Temp>meow
0 1000 2000 3000
10000 11000 12000 13000
20000 21000 22000 23000
There's a workaround:
C:\Temp>type meow.cpp
#include <algorithm>
#include <iostream>
#include <ostream>
#include <vector>
using namespace std;
class Foo {
public:
explicit Foo(const int x) : m_x(x) { }
void mult(vector<vector<int>>& outer) const {
const Foo * const myself = this;
for_each(outer.begin(), outer.end(), [&](vector<int>& inner) {
for_each(inner.begin(), inner.end(), [&](int& elem) {
elem *= myself->m_x;
});
});
}
private:
int m_x;
};
int main() {
Foo f(1000);
vector<vector<int>> v(3, vector<int>(4));
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
v[i][j] = i * 10 + j;
}
}
f.mult(v);
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
cout << v[i][j] << " ";
}
cout << endl;
}
}
C:\Temp>cl /EHsc /nologo /W4 meow.cpp
meow.cpp
C:\Temp>meow
0 1000 2000 3000
10000 11000 12000 13000
20000 21000 22000 23000
C:\Temp>g++ -Wall -Wextra -std=c++0x meow.cpp -o meow.exe
C:\Temp>meow
0 1000 2000 3000
10000 11000 12000 13000
20000 21000 22000 23000