How does the program output 10?

Question

C Quiz by *Asterisk*
https://code.sololearn.com/cU8K0X4CldP2/?ref=app

Answer 1

You might get other results if you try to run the code in different compilers. It looks like the values of b[0], b[1], c and a are stored in four consecutive memory locations, so by changing b[2] you're effectively changing c and by changing b[3] you're changing a.

Answer 2

silentlearner you post a good question. The stated C quiz question is a poor one and should be removed IMHO. Anna has given you the correct explanation already.

Answer 3

You are accessing a place beyond the range of your array (it only goes up to b[1], so you hit a place in memory where something else is stored (in this case your variable a).

Answer 4

you lucky that a and b[3] have the same address. its compiler dependent. if storage is layed out form the top down as (a, c, b[1], b[0]) , then changing b[3] will change a. this is bad programing practice to overrun arrays.

Answer 5

Thomas, b[3] accesses the 4th element, so size of array should be >= 4.

Answer 6

Try this and see b[1] = 10 or b[2] =10

Answer 7

Anna good answer, it make sense.. can you explain in which order the memmory is allocated for auto variable s inside a function..?