1. 数据类型与所占内存大小
类型 |
大小 | 精度 | 注意 |
float | 4 | 7 | |
double | 8 | 15 | 默认 |
long double | 16 | >double |
精度就是有效数字
2. 声明和初始化
float number1 {1.12345678901234567890f}; // Precision : 7 double number2 {1.12345678901234567890}; // Precision : 15 long double number3 {1.12345678901234567890L};
后缀f显式声明变量为float类型,而不用编译器进行转化
后缀L同理
2.1 精度的损失
#include <iomanip> std::cout << std::setprecision(20); // Control the precision from std::cout.
std::cout << "number1 is : " << number1 << std::endl; //7 digits std::cout << "number2 is : " << number2 << std::endl; // around 15 digits std::cout << "number3 is : " << number3 << std::endl; // 15+ digits
标签:1.12345678901234567890,cout,double,float,数据类型,Precision,C++,浮点 From: https://www.cnblogs.com/zspaiprogram/p/17891927.html