无法让for循环工作

Question

第一个for循环它给了我正确的答案，最低为0.00 然而，当我添加第二个for循环以跟踪具有0.00降雨量的月数时，第一个for循环表示“nan”，而第二个for循环表示正确答案为2。

#include <iostream>
using namespace std;
int main(){
    const int NUM = 12;
    string month[NUM] =  {"JAN","FEB","MAR","APR","MAY","JUNE","JULY","AUG","SEPT","OCT","NOV","DEC"};
    int counter = 0;
    float lowest;
    float rainfall [NUM] = {20.75, 34.60, 0.00, 4.12, 1.00, 72.99, 3.76, 10.00,     8.09, 64.05, 0.00, 30.02};
    for (int i = 0; i < NUM; i++) {
        if ((rainfall[i] < rainfall [i-1]) && (rainfall[i] < lowest))
           lowest = rainfall[i];
    }
    cout << lowest << endl;
    for (int i = 0; i < NUM; i++)
    {
        if (rainfall[i] == 0.00)
        counter += 1;
    }
    cout << counter;
    return 0;
}

Answer 1

初始化lowest：

float lowest=100.00;  //or any other term, like INT_MAX

如果没有初始化，您就不会知道lowest可能包含的值，因此在进一步的计算中会给出错误的值。