大多数时候，在竞争性编程中，需要分配变量，数据类型可以容纳的最大值或最小值，但是记住这么大而精确的数字却是一件困难的工作。因此，C++具有某些宏来表示这些数字，因此可以直接将它们分配给变量，而无需实际键入整数。下面列出其中一些列表。
Data Type Range Macro for min value Macro for max value
char -128 to +127 CHAR_MIN CHAR_MAX
short char -128 to +127 SCHAR_MIN SCHAR_MAX
unsigned char 0 to 255 0 UCHAR_MAX
short int -32768 to +32767 SHRT_MIN SHRT_MAX
unsigned short int 0 to 65535 0 USHRT_MAX
int -2147483648 to +2147483647 INT_MIN INT_MAX
unsigned int 0 to 4294967295 0 UINT_MAX
long int -9223372036854775808 to +9223372036854775807 LONG_MIN LONG_MAX
unsigned long int 0 to 18446744073709551615 0 ULONG_MAX
long long int -9223372036854775808 to +9223372036854775807 LLONG_MIN LLONG_MAX
unsigned long long int 0 to 18446744073709551615 0 ULLONG_MAX
float 1.17549e-38 to 3.40282e+38 FLT_MIN FLT_MAX
float(negative) -1.17549e-38 to -3.40282e+38 -FLT_MIN -FLT_MAX
double 2.22507e-308 to 1.79769e+308 DBL_MIN DBL_MAX
double(negative) -2.22507e-308 to -1.79769e+308 -DBL_MIN -DBL_MAX
// C++ code to demonstrate the macros for data types
#include
#include // for int,char macros
#include // for float,double macros
using namespace std;
int main()
{
// Displaying ranges with the help of macros
cout << "char ranges from : " << CHAR_MIN << " to " << CHAR_MAX;
cout << "\n\nshort char ranges from : " << SCHAR_MIN << " to " << SCHAR_MAX;
cout << "\n\nunsigned char ranges from : " << 0 << " to " << UCHAR_MAX;
cout << "\n\n\nshort int ranges from : " << SHRT_MIN << " to " << SHRT_MAX;
cout << "\n\nunsigned short int ranges from : " << 0 << " to " << USHRT_MAX;
cout << "\n\nint ranges from : " << INT_MIN << " to " << INT_MAX;
cout << "\n\nunsigned int ranges from : " << 0 << " to " << UINT_MAX;
cout << "\n\nlong int ranges from : " << LONG_MIN << " to " << LONG_MAX;
cout << "\n\nunsigned long int ranges from : " << 0 << " to " << ULONG_MAX;
cout << "\n\nlong long int ranges from : " << LLONG_MIN << " to " << LLONG_MAX;
cout << "\n\nunsigned long long int ranges from : " << 0 << " to " << ULLONG_MAX;
cout << "\n\n\nfloat ranges from : " << FLT_MIN << " to " << FLT_MAX;
cout << "\n\nnegative float ranges from : " << -FLT_MIN << " to " << -FLT_MAX;
cout << "\n\ndouble ranges from : " << DBL_MIN << " to " << DBL_MAX;
cout << "\n\nnegative double ranges from : " << -DBL_MIN << " to " << +DBL_MAX;
return 0;
}
输出：
char ranges from : -128 to 127
short char ranges from : -128 to 127
unsigned char ranges from : 0 to 255
short int ranges from : -32768 to 32767
unsigned short int ranges from : 0 to 65535
int ranges from : -2147483648 to 2147483647
unsigned int ranges from : 0 to 4294967295
long int ranges from : -9223372036854775808 to 9223372036854775807
unsigned long int ranges from : 0 to 18446744073709551615
long long int ranges from : -9223372036854775808 to 9223372036854775807
unsigned long long int ranges from : 0 to 18446744073709551615
float ranges from : 1.17549e-38 to 3.40282e+38
negative float ranges from : -1.17549e-38 to -3.40282e+38
double ranges from : 2.22507e-308 to 1.79769e+308
negative double ranges from : -2.22507e-308 to 1.79769e+308
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