＜limits.h＞C++标准库

#include<limits.h>

#include<limits.h> 决定了各种变量类型的各种属性。定义在该头文件中的宏限制了各种变量类型（比如char、int和long)的值。这些限制指定了变量不能存储任何超过这些限制的值。
下面的值是特定实现的，且是通过#define指令来定义的，这些值都不得低于下边给出的值。

实例

#include<bits/stdc++.h>
#include<limits.h>
using namespace std;
int main()
{
    
   cout<<"The number of bits in a byte "<<CHAR_BIT<<endl;
   cout<<"The minimum value of SIGNED CHAR = "<<SCHAR_MIN<<endl;
   cout<<"The maximum value of SIGNED CHAR = "<<SCHAR_MAX<<endl;
   cout<<"The maximum value of UNSIGNED CHAR = "<<UCHAR_MAX<<endl;
   cout<<"The minimum value of SHORT INT = "<<SHRT_MIN<<endl;
   cout<<"The maximum value of SHORT INT = "<<SHRT_MAX<<endl;
   cout<<"The minimum value of INT = "<<INT_MIN<<endl;
   cout<<"The maximum value of INT = "<<INT_MAX<<endl;
   cout<<"The minimum value of CHAR = "<<CHAR_MIN<<endl;
   cout<<"The maximum value of CHAR = "<<CHAR_MAX<<endl;
   cout<<"The minimum value of LONG = "<<LONG_MIN<<endl;
   cout<<"The maximum value of LONG = "<<LONG_MAX<<endl;
   return 0;
}

输出

The number of bits in a byte 8
The minimum value of SIGNED CHAR = -128
The maximum value of SIGNED CHAR = 127
The maximum value of UNSIGNED CHAR = 255
The minimum value of SHORT INT = -32768
The maximum value of SHORT INT = 32767
The minimum value of INT = -2147483648
The maximum value of INT = 2147483647
The minimum value of CHAR = -128
The maximum value of CHAR = 127
The minimum value of LONG = -2147483648
The maximum value of LONG = 2147483647