Question

<climits>头文件怎么用？

符号常量要打出来在哪里？main函数里么？比如说：
#include <climits>
int main()
{
INT_MAX
int x;
……
return 0;
}
是这么用么？有什么用呢？可以定义X的取值范围么？

Answer 1

题主的问题有些散乱，所以我就按我的理解说了，符号常量顾名思义就是一个常量，把它当做一个普通的变量就可以了。因为int变量会由于编译器和操作系统位数的不同改变，所以我一般只是用以下的程序看看int等一些类型的取值范围。
题主说定义x的取值范围我不太懂，要是想检测x的取值的话确实可以用个if表达式大于小于地区分一下，可以详细地说一下吗

#include<iostream>
#include<climits>
using namespace std;
int main()
{

cout<<"charBit = "<<CHAR_BIT<<endl<<endl;

cout<<"charMax = "<<CHAR_MAX<<endl;
cout<<"charMin = "<<CHAR_MIN<<endl;
cout<<"unsignedCharMax = "<<UCHAR_MAX<<endl<<endl;

cout<<"signedCharMax = "<<SCHAR_MAX<<endl;
cout<<"signedCharMin = "<<SCHAR_MIN<<endl;
cout<<"unsignedCharMax = "<<UCHAR_MAX<<endl<<endl;

cout<<"shortMax = "<<SHRT_MAX<<endl;
cout<<"shortMin = "<<SHRT_MIN<<endl;
cout<<"unsignedShortMax = "<<USHRT_MAX<<endl<<endl;

cout<<"intMax = "<<INT_MAX<<endl;
cout<<"intMin = "<<INT_MIN<<endl;
cout<<"unsignedInt = "<<UINT_MAX<<endl<<endl;

cout<<"longMax = "<<LONG_MAX<<endl;
cout<<"longMin = "<<LONG_MIN<<endl;
cout<<"unsignedLongMax = "<<ULONG_MAX<<endl;

cin.get();

}