- #include<iostream>
- #include<string>
- #include <limits>
- using namespace std;
- int main()
- {
- cout << "type: \t\t" << "************size**************"<< endl;
- cout << "bool: \t\t" << "所佔字節數：" << sizeof(bool);
- cout << "\t最大值：" << (numeric_limits<bool>::max)();
- cout << "\t\t最小值：" << (numeric_limits<bool>::min)() << endl;
- cout << "char: \t\t" << "所佔字節數：" << sizeof(char);
- cout << "\t最大值：" << (numeric_limits<char>::max)();
- cout << "\t\t最小值：" << (numeric_limits<char>::min)() << endl;
- cout << "signed char: \t" << "所佔字節數：" << sizeof(signed char);
- cout << "\t最大值：" << (numeric_limits<signed char>::max)();
- cout << "\t\t最小值：" << (numeric_limits<signed char>::min)() << endl;
- cout << "unsigned char: \t" << "所佔字節數：" << sizeof(unsigned char);
- cout << "\t最大值：" << (numeric_limits<unsigned char>::max)();
- cout << "\t\t最小值：" << (numeric_limits<unsigned char>::min)() << endl;
- cout << "wchar_t: \t" << "所佔字節數：" << sizeof(wchar_t);
- cout << "\t最大值：" << (numeric_limits<wchar_t>::max)();
- cout << "\t\t最小值：" << (numeric_limits<wchar_t>::min)() << endl;
- cout << "short: \t\t" << "所佔字節數：" << sizeof(short);
- cout << "\t最大值：" << (numeric_limits<short>::max)();
- cout << "\t\t最小值：" << (numeric_limits<short>::min)() << endl;
- cout << "int: \t\t" << "所佔字節數：" << sizeof(int);
- cout << "\t最大值：" << (numeric_limits<int>::max)();
- cout << "\t最小值：" << (numeric_limits<int>::min)() << endl;
- cout << "unsigned: \t" << "所佔字節數：" << sizeof(unsigned);
- cout << "\t最大值：" << (numeric_limits<unsigned>::max)();
- cout << "\t最小值：" << (numeric_limits<unsigned>::min)() << endl;
- cout << "long: \t\t" << "所佔字節數：" << sizeof(long);
- cout << "\t最大值：" << (numeric_limits<long>::max)();
- cout << "\t最小值：" << (numeric_limits<long>::min)() << endl;
- cout << "unsigned long: \t" << "所佔字節數：" << sizeof(unsigned long);
- cout << "\t最大值：" << (numeric_limits<unsigned long>::max)();
- cout << "\t最小值：" << (numeric_limits<unsigned long>::min)() << endl;
- cout << "double: \t" << "所佔字節數：" << sizeof(double);
- cout << "\t最大值：" << (numeric_limits<double>::max)();
- cout << "\t最小值：" << (numeric_limits<double>::min)() << endl;
- cout << "long double: \t" << "所佔字節數：" << sizeof(long double);
- cout << "\t最大值：" << (numeric_limits<long double>::max)();
- cout << "\t最小值：" << (numeric_limits<long double>::min)() << endl;
- cout << "float: \t\t" << "所佔字節數：" << sizeof(float);
- cout << "\t最大值：" << (numeric_limits<float>::max)();
- cout << "\t最小值：" << (numeric_limits<float>::min)() << endl;
- cout << "size_t: \t" << "所佔字節數：" << sizeof(size_t);
- cout << "\t最大值：" << (numeric_limits<size_t>::max)();
- cout << "\t最小值：" << (numeric_limits<size_t>::min)() << endl;
- cout << "string: \t" << "所佔字節數：" << sizeof(string) << endl;
- // << "\t最大值：" << (numeric_limits<string>::max)() << "\t最小值：" << (numeric_limits<string>::min)() << endl;
- cout << "type: \t\t" << "************size**************"<< endl;
- return 0;
- }
/*運行結果分析：
以上結果已經很明白了，一下補充說明幾點：
概念、整型：表示整數、字符和布爾值的算術類型合稱爲整型（integral type）。
關於帶符號與無符號類型：整型 int、stort 和 long 都默認爲帶符號型。要獲得無符號型則必須制定該類型爲unsigned，比如unsigned long。unsigned int類型可以簡寫爲unsigned，也就是說，unsigned後不加其他類型說明符就意味着是unsigned int。
一字節表示八位，即：1byte = 8 bit;
int: 4byte = 32 bit 有符號signed範圍：2^31-1 ~ -2^31即：2147483647 ~ -2147483648無符號unsigned範圍：2^32-1 ~ 0即：4294967295 ~ 0
long: 4 byte = 32 bit 同int型
double: 8 byte = 64 bit 範圍：1.79769e+308 ~ 2.22507e-308
long double: 12 byte = 96 bit 範圍： 1.18973e+4932 ~ 3.3621e-4932
float: 4 byte = 32 bit 範圍： 3.40282e+038 ~ 1.17549e-038
int、unsigned、long、unsigned long 、double的數量級最大都只能表示爲10億，即它們表示十進制的位數不超過10個，即可以保存所有9位整數。而short只是能表示5位；
另外對於浮點說而言：使用double類型基本上不會有錯。在float類型中隱式的精度損失是不能忽視的，二雙精度計算的代價相對於單精度可以忽略。事實上，在有些機器上，double類型比float類型的計算要快得多。float型只能保證6位有效數字，而double型至少可以保證15位有效數字（小數點後的數位），long double型提供的精度通常沒有必要，而且還要承擔額外的運行代價。
double是8字節共64位，其中小數位佔52位，2-^52=2.2204460492503130808472633361816e-16，量級爲10^-16，故能夠保證2^-15的所有精度。
在有些機器上，用long類型進行計算所付出的運行時代價遠遠高於用int類型進行同樣計算的代價，所以算則類型前要先了解程序的細節並且比較long類型與int類型的實際運行時性能代價。