If you wish to generate a Random Number in ABAP you can use the following function module.
QF05_RANDOM_INTEGER
Here you need to input 2 numbers ie the upper limit and the lower limit. This works only for integers.Please find the code below.
REPORT ZEX_RANDOMNUMBER .
Parameters: p_larg like QF00-RAN_INT,
p_small like QF00-RAN_INT.
Data: d_result like QF00-RAN_INT.
CALL FUNCTION 'QF05_RANDOM_INTEGER'
EXPORTING
RAN_INT_MAX = p_larg
RAN_INT_MIN = p_small
IMPORTING
RAN_INT = d_result
EXCEPTIONS
INVALID_INPUT = 1
OTHERS = 2
.
IF SY-SUBRC <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
* WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
Write:/ 'The Number is = ' , d_result.
Parameters: p_larg like QF00-RAN_INT,
p_small like QF00-RAN_INT.
Data: d_result like QF00-RAN_INT.
CALL FUNCTION 'QF05_RANDOM_INTEGER'
EXPORTING
RAN_INT_MAX = p_larg
RAN_INT_MIN = p_small
IMPORTING
RAN_INT = d_result
EXCEPTIONS
INVALID_INPUT = 1
OTHERS = 2
.
IF SY-SUBRC <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
* WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
Write:/ 'The Number is = ' , d_result.
If you enter 100 and 5 then the result would be any number between 5 and 100 inclusive of 5 and 100.