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Range-based for statement

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/*
for( decl : coll) {
    statement
}
*/
for(int i: {2，3，4，5，6，76，7，8，8}) {
    cout<<i<<endl;
}

vector<double> vec;
for(auto elem: vec) {
    cout<< elem <<endl;
}

for(auto& elem: vec) {
    elem *= 3;
}// 关联式容器不能修改值

No explicit type conversions are possible when elements are initialized as decl inside the for loop. Thus, the following does not compile:

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class C {
    public:
       explicit C(const string& s);
    ....
};

vector<string> vs;
for(const C& elem: vs) { // error no conversion from string to C defined
    cout<<elem<<endl;
}