一直不太清楚C语言中浮点数是怎么表示的，这篇文章能回答我的问题👇
浮点表示法
float 共计32位(4字节)
由最高到最低位分别是第31、30、29、......、0位
31位是符号位，1表示该数为负，0反之
30~23位，一共8位是指数位(-128~127)
22~ 0位，一共23位是尾数位
后更。。
20230816
文章目录
C语言中的浮点数表示法声明和初始化浮点数浮点数的精度浮点数运算注意事项参考资料
C语言中的浮点数表示法
浮点数在C语言编程中扮演着重要的角色，尤其是在需要进行科学计算或者处理实数数据时。浮点数允许我们表示小数，它们的精度和范围都比整数类型更大。本文将详细介绍C语言中的浮点数表示法，包括如何声明、初始化和使用浮点数，以及注意事项。
声明和初始化浮点数
在C语言中，我们可以使用float和double关键字来声明浮点数。float通常用于表示单精度浮点数，而double则用于表示双精度浮点数。
float num1;
double num2;
我们还可以在声明的同时初始化浮点数：
float num1 = 3.14f;
double num2 = 3.141592653589793;
注意，如果一个浮点常量后面有f或F后缀，那么它就是float类型。如果没有这些后缀，它就是double类型。
浮点数的精度
在C语言中，float类型通常占用4个字节（32位），而double类型通常占用8个字节（64位）。因此，double类型的浮点数的精度和范围都比float类型的要大。
printf("Size of float: %lu bytes\n", sizeof(float));
printf("Size of double: %lu bytes\n", sizeof(double));
以上代码将分别打印出float和double类型的大小，通常会看到输出结果为：Size of float: 4 bytes 和 Size of double: 8 bytes。
浮点数运算
与整数类似，我们可以对浮点数进行加、减、乘、除等运算。
float num1 = 10.5f, num2 = 3.0f;
printf("num1 + num2 = %.2f\n", num1 + num2);
printf("num1 - num2 = %.2f\n", num1 - num2);
printf("num1 * num2 = %.2f\n", num1 * num2);
printf("num1 / num2 = %.2f\n", num1 / num2);
在上述代码中，%.2f用于指定浮点数的输出格式，其中.2表示保留两位小数。
注意事项
虽然浮点数在处理实数时非常方便，但也存在一些问题。由于浮点数的内部表示方式，有些值可能无法精确表示。例如，0.1无法用二进制浮点数精确表示。因此，在比较浮点数时，我们应该考虑一定的误差范围。
double num1 = 0.1 * 3;
double num2 = 0.3;
if(fabs(num1 - num2) < 1e-10)
printf("num1 and num2 are equal.\n");
else
printf("num1 and num2 are not equal.\n");
在上述代码中，我们使用了fabs函数和一个很小的正数1e-10来判断两个浮点数是否相等。
参考资料
Kernighan, B. W., & Ritchie, D. M. (1988). The C Programming Language. Prentice-Hall.Prata, S. (2013). C Primer Plus. Addison-Wesley.
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