Check a string is number or not

Example for code as below is to check whether a string is number with decimal ','

or not :

REPORT Z_TEST.

DATA: count type i,
LW_CREDIT_TEMP TYPE BSEG-DMBTR.
PARAMETER: p_input TYPE char14.
FIND ALL OCCURRENCES OF ',' IN p_input MATCH COUNT count.
Write: ' occurance of the , = ', count.
IF p_input CO '1234567890, ' and count <= 1.
WRITE: /'Yes, valid', p_input.
write: lw_credit_temp.
Else.
WRITE: /'invalid', p_input.
write: lw_credit_temp.
ENDIF.

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1)Input : 4,5

Output: 4,5 is valid

2)Input: e

output: e is invalid