Error: scalar object 'v' requires one element in initializer
Hello,
I have a simple code shown below saved in a file (say stock_portfolio.cxx).
I am trying to compile this as:
g++ stock_portfolio.cxx
error: scalar object 'v' requires one element in initializer
The gcc version has:
gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-52)
#include<iostream>
#include<vector>
int main() {
std::vector<int>v = {1,2,3,4,5,6};
//std::vector<string> four_star_stocks;
for(int i = 0; i < v.size(); ++i){
std::cout << "Stock S&P: " << v[i] << "\n";
}
std::cout << "========================" << "\n";
std::cout << "Totals : " << v.size() << "\n";
return 0;
}
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list-initialization was only introduced by C ++ in C ++ 11. gcc version 4.1 does not support C ++ 11 (see https://gcc.gnu.org/projects/cxx0x.html )
It is not clear if you are asking a question about a proposed solution / fix or an explanation why your code will not compile.
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Initialize your vector in a loop, for example:
for(int i = 1; i <= 6; ++i)
v.push_back(i);
As cdhowie shows, your version of gcc does not support an initializer list (you need at least g ++ version 4.4,). If you purchase a new one (by adding a flag -std=c++0x
or -std=gnu++0x
), you will see the following:
std::vector<int> v = {1,2,3,4,5,6};
or
If you want to do it with an initializer list, you must use std :: initializer_list like this:
#include <iostream>
#include <vector>
#include <initializer_list>
template <class T>
struct S {
std::vector<T> v;
S(std::initializer_list<T> l) : v(l) {
std::cout << "constructed with a " << l.size() << "-element list\n";
}
void append(std::initializer_list<T> l) {
v.insert(v.end(), l.begin(), l.end());
}
std::pair<const T*, std::size_t> c_arr() const {
return {&v[0], v.size()}; // list-initialization in return statement
// this is NOT a use of std::initializer_list
}
};
template <typename T>
void templated_fn(T) {}
int main()
{
S<int> s = {1, 2, 3, 4, 5}; // direct list-initialization
s.append({6, 7, 8}); // list-initialization in function call
std::cout << "The vector size is now " << s.c_arr().second << " ints:\n";
for (auto n : s.v) std::cout << ' ' << n;
std::cout << '\n';
std::cout << "range-for over brace-init-list: \n";
for (int x : {-1, -2, -3}) // the rule for auto makes this ranged for work
std::cout << x << ' ';
std::cout << '\n';
auto al = {10, 11, 12}; // special rule for auto
std::cout << "The list bound to auto has size() = " << al.size() << '\n';
// templated_fn({1, 2, 3}); // compiler error! "{1, 2, 3}" is not an expression,
// it has no type, and so T cannot be deduced
templated_fn<std::initializer_list<int>>({1, 2, 3}); // OK
templated_fn<std::vector<int>>({1, 2, 3}); // also OK
}
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