C中平方根不打印的向量[重复]

Question

我在制作一个向量时遇到了麻烦，它会返回向量的原始元素平方。

这是我得到的错误。

无操作员“

#include <iostream>
#include <vector>
#include <cmath>

void squareRoot(std::vector<int> &v){

    int x;
    std::vector<int> squared;

    for(auto i:v){
        int x = i*i;
        squared.push_back(x);
    }
    std::cout << squared << std::endl; //error occurs at this line
    return;
}


int main(){

    std::vector<int> v = {2,4,8,1};
    squareRoot(v);

    return 0;
}




Answer 1

您可以定义

std::ostream& operator<<(std::ostream& os, const std::vector<int>& v) {
    os << "[";
    bool first = true;
    for (const auto& x : v) {
        if (first) {
            first = false;
        } else {
            os << ", ";
        }
        os << x;
    }
    os << "]";
    return os;
}

这给了

[4, 16, 64, 1]