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Other Kinds of Checksums in .NET Implementation PDF 417 in .NET Other Kinds of Checksums




How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
Other Kinds of Checksums using barcode implement for .net vs 2010 control to generate, create pdf 417 image in .net vs 2010 applications. Visual Studio 2010 Quite diffe VS .NET PDF-417 2d barcode rent from CRCs are the various techniques used to append a decimal check digit to numbers that are handled by human beings (e.g.

, typed into a computer). Check digits need to be proof against the kinds of highly structured errors that humans tend to make, such as transposing consecutive digits. Wagner and Putter [7] give an interesting introduction to this subject, including speci c algorithms.

Checksums now in widespread use vary from fair to poor. The 10-digit ISBN (International Standard Book Number) that you nd on most books, including this one, uses the check equation 10d1 + 9d2 + 8d3 + + 2d9 + d10 = 0 (mod 11) (20.3.

1). where d10 i s the right-hand check digit. The character X is used to represent a check digit value of 10. Another popular scheme is the so-called IBM check, often.

20. . Less-Numerical Algorithms used for ac .net vs 2010 PDF-417 2d barcode count numbers (including, e.g.

, MasterCard). Here, the check equation is 2#d1 + d2 + 2#d3 + d4 + = 0 (mod 10) (20.3.

2). where 2#d m eans, multiply d by two and add the resulting decimal digits. United States banks code checks with a 9-digit processing number whose check equation is 3a1 + 7a2 + a3 + 3a4 + 7a5 + a6 + 3a7 + 7a8 + a9 = 0 (mod 10) (20.3.

3) The bar code put on many envelopes by the U.S. Postal Service is decoded by removing the single tall marker bars at each end, and breaking the remaining bars into 6 or 10 groups of ve.

In each group the ve bars signify (from left to right) the values 7,4,2,1,0. Exactly two of them will be tall. Their sum is the represented digit, except that zero is represented as 7 + 4.

The 5- or 9-digit Zip Code is followed by a check digit, with the check equation di = 0 (mod 10) (20.3.4).

None of the VS .NET barcode pdf417 se schemes is close to optimal. An elegant scheme due to Verhoeff is described in [7].

The underlying idea is to use the ten-element dihedral group D5 , which corresponds to the symmetries of a pentagon, instead of the cyclic group of the integers modulo 10. The check equation is a1 *f(a2 )*f 2 (a3 )* *f n 1 (an ) = 0 (20.3.

5). where * is (noncommutative) multiplication in D5 , and f i denotes the ith iteration of a certain xed permutation. Verhoeff s method nds all single errors in a string, and all adjacent transpositions. It also nds about 95% of twin errors (aa bb), jump transpositions (acb bca), and jump twin errors (aca bcb).

Here is an implementation:. int decchk( visual .net pdf417 2d barcode char string[], int n, char *ch) Decimal check digit computation or veri cation. Returns as ch a check digit for appending to string[1.

.n], that is, for storing into string[n+1]. In this mode, ignore the returned boolean (integer) value.

If string[1..n] already ends with a check digit (string[n]), returns the function value true (1) if the check digit is valid, otherwise false (0).

In this mode, ignore the returned value of ch. Note that string and ch contain ASCII characters corresponding to the digits 0-9, not byte values in that range. Other ASCII characters are allowed in string, and are ignored in calculating the check digit.

{ char c; int j,k=0,m=0; static int ip[10][8]={0,1,5,8,9,4,2,7,1,5, 8,9,4,2,7,0,2,7,0,1, 5,8,9,4,3,6,3,6,3,6, 3,6,4,2,7,0,1,5,8,9, 5,8,9,4,2,7,0,1,6,3, 6,3,6,3,6,3,7,0,1,5, 8,9,4,2,8,9,4,2,7,0, 1,5,9,4,2,7,0,1,5,8}; static int ij[10][10]={0,1,2,3,4,5,6,7,8,9, 1,2,3,4,0,6,7,8,9,5, 2,3,4,0,1,7,8,9,5,6, 3,4,0,1,2,8,9,5,6,7, 4,0,1,2,3,9,5,6,7,8, 5,9,8,7,6,0,4,3,2,1, 6,5,9,8,7,1,0,4,3,2, 7,6,5,9,8,2,1,0,4,3, 8,7,6,5,9,3,2,1,0,4, 9,8,7,6,5,4,3,2,1,0}; Group multiplication and permutation tables. for (j=0;j<n;j++) { c=string[j]; if (c >= 48 && c <= 57) Look at successive characters. Ignore everything except digits.

. 20.4 Huffman Coding and Compression of Data k=ij[k][ip[ barcode pdf417 for .NET (c+2) % 10][7 & m++]]; } for (j=0;j<=9;j++) Find which appended digit will check properly. if (!ij[k][ip[j][m & 7]]) break; *ch=j+48; Convert to ASCII.

return k==0; }. CITED REFER ENCES AND FURTHER READING: McNamara, J.E. 1982, Technical Aspects of Data Communication, 2nd ed.

(Bedford, MA: Digital Press). [1] da Cruz, F. 1987, Kermit, A File Transfer Protocol (Bedford, MA: Digital Press).

[2] Morse, G. 1986, Byte, vol. 11, pp.

115 124 (September). [3] LeVan, J. 1987, Byte, vol.

12, pp. 339 341 (November). [4] Sarwate, D.

V. 1988, Communications of the ACM, vol. 31, pp.

1008 1013. [5] Grif ths, G., and Stones, G.

C. 1987, Communications of the ACM, vol. 30, pp.

617 620. [6] Wagner, N.R.

, and Putter, P.S. 1989, Communications of the ACM, vol.

32, pp. 106 110. [7].

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