调试断言失败。C++向量下标超出范围。

the following code fills the vector with 10 values in first for loop. in second for loop i want the elements of vector to be printed. The output is till the cout statement before the j loop.Gives error of vector subscript out of range.

下面的代码在第一个循环中填充了10个值的向量。在第二个for循环中，我想要打印出向量的元素。输出是在j循环之前的cout语句。在范围内给出矢量下标的错误。

#include "stdafx.h"
#include "iostream"
#include "vector"
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{   vector<int> v;

    cout<<"Hello India"<<endl;
    cout<<"Size of vector is: "<<v.size()<<endl;
    for(int i=1;i<=10;++i)
    {
        v.push_back(i);

    }
    cout<<"size of vector: "<<v.size()<<endl;

    for(int j=10;j>0;--j)
    {
        cout<<v[j];
    }

    return 0;
}

2 个解决方案

#1

Regardless of how do you index the pushbacks your vector contains 10 elements indexed from 0 (0, 1, ..., 9). So in your second loop v[j] is invalid, when j is 10.

不管你如何索引，你的向量包含10个元素从0(0,1，…)所以在第二个循环中v[j]是无效的，当j是10时。

This will fix the error:

这将修正错误:

for(int j = 9;j >= 0;--j)
{
    cout << v[j];
}

In general it's better to think about indexes as 0 based, so I suggest you change also your first loop to this:

一般来说，最好把索引设为0，所以我建议你也改变一下你的第一个循环:

for(int i = 0;i < 10;++i)
{
    v.push_back(i);
}

#2

v has 10 element, the index starts from 0 to 9.

v有10个元素，指数从0到9。

for(int j=10;j>0;--j)
{
    cout<<v[j];   // v[10] out of range
}

you should update for loop to

您应该更新for循环。

for(int j=9; j>=0; --j)
//      ^^^^^^^^^^
{
    cout<<v[j];   // out of range
}

Or use reverse iterator to print element in reverse order

或者使用反向迭代器以相反的顺序打印元素。

for (auto ri = v.rbegin(); ri != v.rend(); ++ri)
{
  std::cout << *ri << std::endl;
}

#1