c++ - 不匹配 ‘operator<’

Question

这可能是一个非常快速的修复，但我无法弄清楚为什么会出现错误。

代码:

#include <iostream>
#include <queue>
#include <vector>
#include <iomanip>
#include <stdlib.h>
#include <time.h>

using namespace std;

int main(int argc, char *argv[]){

    srand ( time(NULL) );
    double randomNumber = (double)(rand() % 100) / 100;

    string numCars;

    cout << "\nPlease enter the number of cars going through the intersection:" << endl;
    cout << "->";
    getline (cin, numCars);

    for(double i=0; i<numCars; i++){
        cout << randomNumber << endl;
    }

}

错误是:

 traffic.cpp:80: error: no match for ‘operator<’ in ‘i < numCars’

Answer 1

numCars 是一个字符串。它应该是整数类型(char、short、int、long)