How to count the occurrence of a number?

Shell Programming and Scripting
1

Hi,

I have a file which contained a set of numbers like

Col1 col2 col3 col4
1 sa 13 0
2 sb 14 0
3 sc 15 9
4 sd 16 -9
5 sd 20 -2
6 sd 20 4

Here in last column I need to count the zeros, positive values and negative values,
please help me to do that.

2 
awk '$NF < 0 {a[-1]++} $NF == 0 {a[0]++} $NF > 0 {a[1]++} END {print "Neg: "a[-1], "Zero: "a[0], "Pos: "a[1]}' file
3 
awk 'NR>1 && $NF==0{A[0]++}
    NR>1 && $NF<1{A[-1]++}
    NR>1 && $NF>1{A[1]++}
    END{print "Zero - "A[0],"Positive - "A[1],"Negative - "A[-1]}" file