说明符

2019-11-08 02:29:39

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C++中有4种说明符:short、long、singed、unsigned 这里写图片描述

说明符short、long的使用 这里写图片描述

signed、unsigned unsigned不保留符号位，即有一个多余的位可以用，所以比signed能存储的数大两倍。通过规定unsigned char，可以强制使用符号位 通过sizeof运算符显示不同数据类型的大小

#include<iostream>using namespace std;int main(){ //要把诸如unsigned short看为一种数据类型 //char char c; //1 unsigned char cu; //1 //int int i; //4 unsigned int iu; //4 short int is; //2 short iis;//这样定义和short int一样 unsigned short int isu; //2 unsigned short iisu; //4 long int il; //4 long iil; unsigned long int ilu; //4 unsigned long iilu; //浮点型 float f; //4 double d; //8 long double ld; //8 //打印大小 cout <<"/n char= " << sizeof(c) <<"/n unsigned char= " << sizeof(cu) <<"/n int = " << sizeof(i) <<"/n unsigned int= " << sizeof(iu) <<"/n short = " << sizeof(is) <<"/n unsigned short= " << sizeof(isu) <<"/n long= " << sizeof(il) <<"/n unsigned long= " << sizeof(ilu) <<"/n float= " << sizeof(f) <<"/n double= " << sizeof(d) <<"/n long double= " << sizeof(ld) <<std::endl; return 0;}

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