添加来自此值之前的向量的第二个值(Adding the second values from a vector which appear before this value)

 所以，我试图创建一个通过对向量移位的函数，并将先前值的第二个值添加到当前目标。 但是，我不确定如何向后循环以获取之前在目标之前的所有值。 
 
 以下是我迄今为止所做的： 
 
int cWeight (KEY_T key) const
{
    int size = _valueToWeightMap.size();

    for (int x = 0; x < size; x++)
    {
        if (_valueToWeightMap[x].first == key && x == 0)
            return _valueToWeightMap[x].second;

        if (_valueToWeightMap[x].first == key && x != 0)
            return _valueToWeightMap[x].second + _valueToWeightMap[x - 1].second;
    }

    return 0;
}
 
 _valueToWeightMap是向量的名称，而KEY_T只是查找字符串的类型名称。 
 
 目前，该函数只捕获矢量中右对齐的二次值，但我希望它从它后面的所有对象中获取二次值。 我该怎么做呢？ 
 
 这是我添加到矢量中的一些东西。 
 
dist1.add("Helmet", 1);
dist1.add("Boots", 10);
dist1.add("Gloves", 20);
dist1.add("Cloud", 15);
dist1.add("Ring", 4);
dist1.add("Wind", 12);
 
 所以，我想要的功能是这样的： 
 
 
 
 位置0中的对的第二个值等于1，因此该函数应返回一个。 
 
 
 位置1中的对的第二个值等于10，因此函数应返回11.（10 + 1） 
 
 
 位置2中的对具有等于20的第二个值，所以它应该返回31.（20 + 10 + 1）等等。 
 

So, I'm attempting to make a function that shifts through a vector of pairs and adds the second value of to the previous values to the current target. However, I'm unsure of how to loop backwards to grab all of the values that were previously before the target.
 
Here's what I have done so far:
 
int cWeight (KEY_T key) const
{
    int size = _valueToWeightMap.size();

    for (int x = 0; x < size; x++)
    {
        if (_valueToWeightMap[x].first == key && x == 0)
            return _valueToWeightMap[x].second;

        if (_valueToWeightMap[x].first == key && x != 0)
            return _valueToWeightMap[x].second + _valueToWeightMap[x - 1].second;
    }

    return 0;
}
 
The _valueToWeightMap is the name of the vector, and KEY_T is just a typename that looks for strings.
 
Currently, the function only grabs the secondary value from the pair right behind it in the vector, however I want it to grab the secondary value from all the ones behind it. How would I go about doing this? 
 
Here's some things I added to the vector.
 
dist1.add("Helmet", 1);
dist1.add("Boots", 10);
dist1.add("Gloves", 20);
dist1.add("Cloud", 15);
dist1.add("Ring", 4);
dist1.add("Wind", 12);
 
So, what I want the function to do is this:
 
 
 
The pair in position 0 has its second value equal to 1, so the function should return one.
 
 
The pair in the position 1 has its second value equal to 10, so the function should return 11. (10 + 1)
 
 
The pair in position 2 has its second value equal to 20, so it should return 31. (20 + 10 + 1) and so on.
 

原文：https://stackoverflow.com/questions/46946404