Question

我收到以下错误。我该如何解决？

错误消息

Vector.cpp:9:49: error: expected ';' after expression
if (i < 0 || size() <= i) throw out_of_range{"Vector::operator[]"};
                                            ^
                                            ;
Vector.cpp:9:37: error: use of undeclared identifier 'out_of_range'
if (i < 0 || size() <= i) throw out_of_range{"Vector::operator[]"};
                                ^
Vector.cpp:9:70: error: expected ';' after expression
if (i < 0 || size() <= i) throw out_of_range{"Vector::operator[]"};

user.cpp

#include <iostream>
#include <cmath>

#include "Vector.h"

using namespace std;

double sqrt_sum(Vector& v)
{
    double sum = 0;
    for (int i = 0; i != v.size(); ++i)
        sum += sqrt(v[i]);
    return sum;
}

int main() {
    Vector v(1);
    int sum = sqrt_sum(v);
    cout << sum << endl;
}

Vector.h

class Vector
{
    public:
        Vector(int s);
        double& operator[](int i);
        int size();
    private:
        double* elem;
        int sz;
};

Vector.cpp

#include "Vector.h"

Vector::Vector(int s):elem {new double[s]}, sz{s} 
{
}

double& Vector::operator[](int i)
{
    if (i < 0 || size() <= i) throw out_of_range{"Vector::operator[]"}; // it works when this line is commented out
    return elem[i];
}

int Vector::size()
{
    return sz;
}

tasks.json

{
    "version": "0.1.0",
    "command": "g++",
    "isShellCommand": true,
    "args": ["-std=c++11", "-O2", "-g", "user.cpp", "Vector.cpp"],
    "showOutput": "always"
}

更新1

我添加了以下两行，然后就可以了。

#include <iostream>
#include "Vector.h"
using namespace std;

Answer 1

尝试包含例外标题：

#include <stdexcept>

如此example所示。

请勿忘记使用命名空间std，或使用std::解析范围。

错误：使用未声明的标识符＆＃39; out_of_range＆＃39;在vscode上

1 个答案: