Vikramjeet

C language do not perform any bounds check on array during run time, so it will not give any error if you are doing so. But technically its not right to do so, because the memory location you are using or manipulating anything may contain some very sensitive information, which may other program are using, can lead to crash the program or machine itself..

In C language array will always starts with index 0, while there are some other languages which offers 1 as the lower index and also some languages have user defined lower and upper bounds, refer to wiki for more details : https://en.wikipedia.org/wiki/Comparison_of_programming_languages_(array) The technical reason is that C is supposed to be an efficient language. Arrays are stored in contiguous memory locations. So let say, starts at address 1000, the first element of the array will be at 1000. So, if we have indices starting at 1, the compiler would have to subtract one before it can find the actual memory address of the element , Address of an element : baseaddress + ((index-1) * sizeof(element)). In the case of 0-based indices, there is no need to subtract anything, because baseaddress + (index * sizeof(element)) gives us the appropriate address.