C/C++中各种类型int、long、double、char表示范围(最大最小值) Love The Way You Lie 2022-08-21 10:56 142阅读 0赞 **\[cpp\]** [view plain][] [copy][view plain] 1. \#include<iostream> 2. \#include<string> 3. \#include <limits> 4. **using** **namespace** std; 5. 6. **int** main() 7. \{ 8. cout << "type: \\t\\t" << "\*\*\*\*\*\*\*\*\*\*\*\*size\*\*\*\*\*\*\*\*\*\*\*\*\*\*"<< endl; 9. cout << "bool: \\t\\t" << "所占字节数:" << **sizeof**(**bool**); 10. cout << "\\t最大值:" << (numeric\_limits<**bool**>::max)(); 11. cout << "\\t\\t最小值:" << (numeric\_limits<**bool**>::min)() << endl; 12. cout << "char: \\t\\t" << "所占字节数:" << **sizeof**(**char**); 13. cout << "\\t最大值:" << (numeric\_limits<**char**>::max)(); 14. cout << "\\t\\t最小值:" << (numeric\_limits<**char**>::min)() << endl; 15. cout << "signed char: \\t" << "所占字节数:" << **sizeof**(**signed** **char**); 16. cout << "\\t最大值:" << (numeric\_limits<**signed** **char**>::max)(); 17. cout << "\\t\\t最小值:" << (numeric\_limits<**signed** **char**>::min)() << endl; 18. cout << "unsigned char: \\t" << "所占字节数:" << **sizeof**(unsigned **char**); 19. cout << "\\t最大值:" << (numeric\_limits<unsigned **char**>::max)(); 20. cout << "\\t\\t最小值:" << (numeric\_limits<unsigned **char**>::min)() << endl; 21. cout << "wchar\_t: \\t" << "所占字节数:" << **sizeof**(**wchar\_t**); 22. cout << "\\t最大值:" << (numeric\_limits<**wchar\_t**>::max)(); 23. cout << "\\t\\t最小值:" << (numeric\_limits<**wchar\_t**>::min)() << endl; 24. cout << "short: \\t\\t" << "所占字节数:" << **sizeof**(**short**); 25. cout << "\\t最大值:" << (numeric\_limits<**short**>::max)(); 26. cout << "\\t\\t最小值:" << (numeric\_limits<**short**>::min)() << endl; 27. cout << "int: \\t\\t" << "所占字节数:" << **sizeof**(**int**); 28. cout << "\\t最大值:" << (numeric\_limits<**int**>::max)(); 29. cout << "\\t最小值:" << (numeric\_limits<**int**>::min)() << endl; 30. cout << "unsigned: \\t" << "所占字节数:" << **sizeof**(unsigned); 31. cout << "\\t最大值:" << (numeric\_limits<unsigned>::max)(); 32. cout << "\\t最小值:" << (numeric\_limits<unsigned>::min)() << endl; 33. cout << "long: \\t\\t" << "所占字节数:" << **sizeof**(**long**); 34. cout << "\\t最大值:" << (numeric\_limits<**long**>::max)(); 35. cout << "\\t最小值:" << (numeric\_limits<**long**>::min)() << endl; 36. cout << "unsigned long: \\t" << "所占字节数:" << **sizeof**(unsigned **long**); 37. cout << "\\t最大值:" << (numeric\_limits<unsigned **long**>::max)(); 38. cout << "\\t最小值:" << (numeric\_limits<unsigned **long**>::min)() << endl; 39. cout << "double: \\t" << "所占字节数:" << **sizeof**(**double**); 40. cout << "\\t最大值:" << (numeric\_limits<**double**>::max)(); 41. cout << "\\t最小值:" << (numeric\_limits<**double**>::min)() << endl; 42. cout << "long double: \\t" << "所占字节数:" << **sizeof**(**long** **double**); 43. cout << "\\t最大值:" << (numeric\_limits<**long** **double**>::max)(); 44. cout << "\\t最小值:" << (numeric\_limits<**long** **double**>::min)() << endl; 45. cout << "float: \\t\\t" << "所占字节数:" << **sizeof**(**float**); 46. cout << "\\t最大值:" << (numeric\_limits<**float**>::max)(); 47. cout << "\\t最小值:" << (numeric\_limits<**float**>::min)() << endl; 48. cout << "size\_t: \\t" << "所占字节数:" << **sizeof**(**size\_t**); 49. cout << "\\t最大值:" << (numeric\_limits<**size\_t**>::max)(); 50. cout << "\\t最小值:" << (numeric\_limits<**size\_t**>::min)() << endl; 51. cout << "string: \\t" << "所占字节数:" << **sizeof**(string) << endl; 52. // << "\\t最大值:" << (numeric\_limits<string>::max)() << "\\t最小值:" << (numeric\_limits<string>::min)() << endl; 53. cout << "type: \\t\\t" << "\*\*\*\*\*\*\*\*\*\*\*\*size\*\*\*\*\*\*\*\*\*\*\*\*\*\*"<< endl; 54. **return** 0; 55. \} ![1351591412_5204.PNG][] /\*运行结果分析: 以上结果已经很明白了,一下补充说明几点: 概念、整型:表示整数、字符和布尔值的算术类型合称为整型(integral type)。 关于带符号与无符号类型:整型 int、stort 和 long 都默认为带符号型。要获得无符号型则必须制定该类型为unsigned,比如unsigned long。unsigned int类型可以简写为unsigned,也就是说,unsigned后不加其他类型说明符就意味着是unsigned int。 一字节表示八位,即:1byte = 8 bit; int: 4byte = 32 bit有符号signed范围:2^31-1 ~ -2^31即:2147483647 ~ -2147483648无符号unsigned范围:2^32-1 ~ 0即:4294967295 ~ 0 long: 4 byte = 32 bit同int型 double: 8 byte = 64 bit范围:1.79769e+308 ~ 2.22507e-308 long double: 12 byte = 96 bit范围: 1.18973e+4932 ~ 3.3621e-4932 float: 4 byte = 32 bit范围: 3.40282e+038 ~ 1.17549e-038 int、unsigned、long、unsigned long 、double的数量级最大都只能表示为10亿,即它们表示十进制的位数不超过10个,即可以保存所有9位整数。而short只是能表示5位; 另外对于浮点说而言:使用double类型基本上不会有错。在float类型中隐式的精度损失是不能忽视的,二双精度计算的代价相对于单精度可以忽略。事实上,在有些机器上,double类型比float类型的计算要快得多。float型只能保证6位有效数字,而double型至少可以保证15位有效数字(小数点后的数位),long double型提供的精度通常没有必要,而且还要承担额外的运行代价。 double是8字节共64位,其中小数位占52位,2-^52=2.2204460492503130808472633361816e-16,量级为10^-16,故能够保证2^-15的所有精度。 在有些机器上,用long类型进行计算所付出的运行时代价远远高于用int类型进行同样计算的代价,所以算则类型前要先了解程序的细节并且比较long类型与int类型的实际运行时性能代价。 [view plain]: http://blog.csdn.net/xuexiacm/article/details/8122267# [1351591412_5204.PNG]: https://img-my.csdn.net/uploads/201210/30/1351591412_5204.PNG
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