c++ - 为什么我的命令行参数处理会使我的程序崩溃？

Question

为什么看起来如此简单的事情会导致我的程序崩溃？

我正在尝试获取一个值，n以使数组的大小N和对其执行各种操作，但这不是重点。无论如何，每次我尝试访问时它都会崩溃argv[1]。

int main(int argc, char * argv[])
{
  int n;
  n = atoi(argv[1]); //Crashes here!
  cout << "\nN: " << n << endl;
}

Answer 1

Does argv[1] exist? To prevent your code from accessing memory it should not check how many arguments were passed.

if(argc >= 2)
  n = argv[1];
else
  std::cout << "Proper usage: .....\n";

This seems like a great time to learn how to use your debugger to view the contents of argv and argc.