BASIC COMPARE Function

COMPARE

TYPE: plusBASIC relational function

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FORMAT: COMPARE ( * array1, * array2 )

Action: Compares two arrays.

• array1 and array2 are array variable names with no parentheses after them.
  • Undimensioned array error if either array has not be defined with the DIM statement.
• Returns:
  • -1 (True) if both arrays contain identical data.
  • 0 (False) if the array contents differ or the array sizes are not the same.

Examples:

DIM A(1),B(1),C(2)
PRINT COMPARE(*A,*B)
PRINT COMPARE(*A,*C)
A(1)=9
PRINT COMPARE(*A,*B)

Prints -1, 0, and 0

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FORMAT: COMPARE ( [ @ page1 , ] address1 , [ @ page2 ,] address2 , length )

Action: Compares two sections of memory.

• page1 and page2 are optional page numbers.
  • An @ page argument causes memory in that page to be used for comparison
• address1 and address2 are the starting addresses of each section of memory to be compared.
• length is the total number of bytes to compare.
• Returns -1 if the sections contents are identical, otherwise returns 0.

Examples:

PRINT COMPARE(15000,32000,256)

Returns -1 if the 256 bytes starting at address 15000 match the 256 bytes starting at address 32000.

PRINT COMPARE(@40,100,20000,200)

Compares 200 bytes at address 100 of page 40 with 200 bytes at address 20000 in main memory.

PRINT COMPARE(12288,@41,0,1024)

Compares 1024 bytes of memory at address 12288 in main memory with 1024 bytes at address 0 of page 41.

PRINT COMPARE(@50,500,@51,1000,500)

Compares 200 bytes at address 50 of page 50 with 1024 bytes at address 0 of page 51.