Check, pronounced in Chinese as jio yàn, is a way to correct data errors in data transmission, which is divided into odd-numbered check and even-numbered check.
Code: ?ㄚˇ. The radical "Ma" is simplified to "Ma". Save strokes and simplify them according to ancient calligraphy. From the sound of stones and horses. The hard block assembled by fine earth in Shanchang is a model of stone. Horses hold their heads up angrily and bravely show their tails, which is the horse's paradigm. The superposition of the two paradigms of stone horse. Forming a hard horse is the paradigm of code.
The check code is usually the last bit of a group of numbers, which is obtained by some operation from the previous numbers to check the correctness of this group of numbers. Common check codes include the last digit of China ID card and the last digit of ISBN number.
Inspection principle
A verification program based on a verification formula derived from a verification method is preset in the system. When a code with a check code is input into the system, the system uses a verification program to calculate the input ontology code to obtain a verification result, and then compares the verification result with the check code of the input code to check whether the input is correct.
If they are consistent, it means that the code is entered correctly and the system allows input; If they are inconsistent, it means that the code has been entered incorrectly, and the system refuses to enter it, requiring re-entry of the code.
Check code algorithm: Different check codes often have different algorithms. Common check code algorithms include: code distance, parity check, Hamming check, cyclic redundancy check, etc.