c++ - sublime text C++ 编译导致段错误

Question

我最近从 windows 上的 dev c++ 切换到 osx 开发环境，并尝试使用 sublime text 3。但是，当我运行我的程序时，出现段错误。这是错误消息:

/bin/bash: line 1: 20506 Segmentation fault: 11  "/Users/jimi/Documents/University/lab0603"
[Finished in 1.2s with exit code 139]
[shell_cmd: g++ "/Users/jimi/Documents/University/lab0603.cpp" -o "/Users/jimi/Documents/University/lab0603" && "/Users/jimi/Documents/University/lab0603"]
[dir: /Users/jimi/Documents/University]
[path: /usr/bin:/bin:/usr/sbin:/sbin]

完整代码如下:

#include <iostream>
#include <cmath>

using namespace std;


string flightDirections[16] = {"ENE", "NE", "NNE", "N", "NNW", "NW", "WNW", "W", "WSW", "SW", "SWS", "S", "SSE", "SE", "ESE", "E"};
double cruisingSpeed = 0;
double windSpeed = 0;
int windDirection = 0;
double flightDistance = 0;

string numberToDirection(int direction) {

    return (direction) ? "The wind is blowing from the East." : " The wind is blowing from the West.";

    //this way we only have one return statement :)

}

void getInput () {
    cout << "Hello! \n"
         << "Thank you for choosing to use this really great program!! \n"
         << "This program will compute the necessary heading adjustment for your flight,"
         << " and provide the estimated flight time. \n";
    cout << "Enter the aircraft cruising speed in still air (in km/h): ";
    cin >> cruisingSpeed;
    cout << " \n \t cruising speed = " << cruisingSpeed << "\n Enter the wind speed in km/h: ";
    cin >>  windSpeed;
    cout << " \n \t wind speed = " << windSpeed << "\n Enter 1 if the wind is blowing from the West and -1 if wind is blowing from the East:";
    cin >> windDirection;
    cout << "\n\t" << numberToDirection(windDirection) << "\n Enter the distance between the originating and destination cities, in km:";
    cin >> flightDistance;
    cout << "\n\t flight distance = " << flightDistance << "\n Enter the compass direction of the destination city, relative to the originating cities, using the following values:";
    for (int i = 0; i < sizeof(flightDirections); i++) {
        cout << i + 1;
        cout << flightDirections[i];
    }
    cin.ignore();


}

int main() {


    getInput();
    return 0;

}

这是怎么回事？

Answer 1

您的问题出在您的 for 循环上。

for (int i = 0; i < sizeof(flightDirections); i++) 

由于 sizeof(flightDirections) 大于数组的大小，因此将超出数组的末尾。 sizeof(flightDirections) 是 sizeof(std::string) * number_of_elements_in_the_array。为了获得正确大小的数组，您需要使用

sizeof(flightDirections) / sizeof(flightDirections[0])

或者更好的是使用 ranged based for loop作为

int i = 0;
for (const auto & e : flightDirections) {
    cout << ++i << e;
}