Single variables can take positive or negative values ranging from 3.402823 x 10E+38 to 1.401298 x 10E-45. Single variables are floating-point variables, in which the decimal precision decreases as the non-decimal part of the number increases. Single variables are suitable for mathematical calculations of average precision. Calculations require more time than for Integer variables, but are faster than calculations with Double variables. A Single variable requires 4 bytes of memory. The type-declaration character is &quot; ! &quot; .
单精度类型的变量可以取的正负值范围为3.402823 x 10E38 到1.401298 x 10E-45。单精度变量是浮点变量，其小数精度会随着非小数部分位数的增加而降低。 & & legal; 单精度变量适合进行平均精度的数学计算。 & & legal; 其计算速度比整数变量的计算速度慢，但比双精度变量的计算速度快。 & & legal; 单精度变量需要四个字节的内存。 & & legal; 类型声明符是 “!”。