我用 C++ Primary Plus 编写了关于变量大小的程序 这是代码:
#include <iostream>
#include <climits>
using namespace std;
int main() {
int n_int = INT_MAX;
short n_short = SHRT_MAX;
long n_long = LONG_MAX;
long long n_llong = LLONG_MAX;
// wielkosc
cout << "int is " << sizeof (int) << " bytes." << endl;
cout << "short is " << sizeof n_short << " bytes."<< endl;
cout << "long is " << sizeof n_long << " bytes." << endl;
cout << "long long is " << sizeof n_llong << " bytes." << endl;
cout << endl;
cout << "Maximum values: "<< endl;
cout << "int: " << n_int << endl;
cout << "short: " << n_short << endl;
cout << "long: " << n_long << endl;
cout << "long long: " << n_llong<< endl << endl;
cout << "Minimum int value = " << INT_MIN << endl;
cout << "Bits per byte = " << CHAR_BIT << endl;
return 0;
}
当我在 Eclipse IDE 中用 Cygwin 编译它并运行它时，告诉我 LONG_MAX = 9223372036854775807，这是不正确的，我做错了什么？谢谢。
实际输出:
int is 4 bytes. short is 2 bytes. long is 8 bytes. long long is 8 bytes. Maximum values: int: 2147483647 short: 32767 long: 9223372036854775807 long long: 9223372036854775807 Minimum int value = -2147483648 Bits per byte = 8
预期输出:
int is 4 bytes. short is 2 bytes. long is 8 bytes. long long is 8 bytes. Maximum values: int: 2147483647 short: 32767 long: 2 147 483 647 long long: 9223372036854775807 Minimum int value = -2147483648 Bits per byte = 8
最佳答案
你为什么这么确定LONG_MAX != 9223372036854775807？这对我来说似乎很好，因为 2^63 -1 == 9223372036854775807。这意味着长整型在您的实现中是 64 位，第一位用作符号位。请记住，标准并未具体指定所有不同数据类型的大小 - 在 Visual Studio 的编译器上，long 与 int 的大小相同，这有点烦人;)
关于c++ - LONG_MAX Cygwin 的大小，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30288804/