Matlab里面的四个函数：Floor, Ceil, Fix, Round

B = floor(A)       即floor：朝负无穷方向舍入
 
B = ceil(A)         即ceil：朝正无穷方向舍入
 
B = fix(A)           即fix：朝零方向舍入
 
B = round(A)     即round：四舍五入
 

a = [-1.9, -0.2, 3.4, 5.6, 7.0, 2.4+3.6i]

 
a =Columns 1 through 4
-1.9000            -0.2000             3.4000             5.6000         Columns 5 through 6
   7.0000             2.4000 + 3.6000i
 
floor(a)  ans =
Columns 1 through 4
-2.0000            -1.0000             3.0000             5.0000         Columns 5 through 6
   7.0000             2.0000 + 3.0000i
 
ceil(a) ans =
Columns 1 through 4
-1.0000            0             4.0000             6.0000Columns 5 through 6
   7.0000             3.0000 + 4.0000i
 
fix(a) ans =
Columns 1 through 4
-1.0000                  0             3.0000             5.0000         Columns 5 through 6
   7.0000             2.0000 + 3.0000i
 
round(a) ans =
Columns 1 through 4
-2.0000                  0
4000
             3.0000             6.0000
Columns 5 through 6
   7.0000             2.0000 + 4.0000i