初始化(new)

#include<iostream>
using namespace std;

int init0;
int main()
{
    //这2个都是c++11新支持的东东 
    int a = {3};//无警告!!!
    int b{2};//extended initializer lists only available with -std=c++11 or -std=gnu++11 [默认启用]
    cout << a << endl;
    cout << b << endl;

    long double c = 123.123456789;
    //这一行代码居然只是警告！按书上说应该是个error啊
    int d{c},e={c};//narrowing conversion of ‘c’ from ‘long double’ to ‘int’ inside { } is ill-formed in C++11 [-Wnarrowing]
    cout << d << endl;
    cout << e << endl;

    int init1;
    cout << "init0:" << init0 << endl;
    cout << "init1:" << init1 << endl;
    return 0;
}


3
2
123
123
init0:0
init1:134519912

一直觉得变量不初始化就是万恶之源，可为什么c++不给函数内的变量一个default value呢？