http://courses.cs.taltech.ee/w/index.php?action=history&feed=atom&title=Stack_Exploration_%28ITS8020%29 2026-05-21T19:02:19Z Selle lehekülje redigeerimiste ajalugu MediaWiki 1.35.9 http://courses.cs.taltech.ee/w/index.php?title=Stack_Exploration_(ITS8020)&diff=7046&oldid=prev 2018-09-14T05:38:53Z

<p>Uus lehekülg: &#039;{{its8020}} In preparation for memory management, we shall investigate [http://en.wikipedia.org/wiki/Call_stack call stack] contents. == Task == Write some small program for fu...&#039;</p> <p><b>Uus lehekülg</b></p><div>{{its8020}}<br /> In preparation for memory management, we shall investigate [http://en.wikipedia.org/wiki/Call_stack call stack] contents.<br /> <br /> == Task ==<br /> <br /> Write some small program for further exploration. The program should contain:<br /> * function main() containing:<br /> ** at least 3 integers, with some (different) default values<br /> ** a string<br /> * function void foo(int argument) containing:<br /> ** at least 2 integers, with some default values<br /> This base program can do practically anything (including nothing), as long as the function foo() runs.<br /> <br /> # Modify the program to print the &#039;&#039;memory addresses&#039;&#039; of all the variables. Use &quot;%p&quot; for [http://linux.die.net/man/3/printf printf()] function. Use &amp; operator on the variable to get the memory address as a value.<br /> # Within function foo(), use the memory address of the first declared variable to print out the value of address which precedes it and the memory address which follows it. (Use * operator to read memory from given location)<br /> # Can you go further? Can you read the variables of main() just by modifying the address of a variable in foo()? (&#039;&#039;Yes, but try it out&#039;&#039;)<br /> # Can you print the string from main()? Is it located in the stack?<br /> // note that there is a difference between the lines:<br /> char s[] = &quot;foo:asdasdasd&quot;; // is allocated on the stack<br /> char *s = &quot;bar:dsadsadas&quot;; // is not allocated on the stack<br /> # Comment some of the lines which print the addresses of variables in main() (from task 1), check that your program does not use them -- can you still print them by using an address from foo()?<br /> # Put the variables back to the stack. Write a function which tries to print out all the stack (4 bytes per line using printf() with &quot;%08x\n&quot;. The program should crash at some point with a segmentation fault; this is the expected and desired result of the task and should be valued!<br /> : Note: For your convenience print the memory location address, then its contents as decimal, hexadecimal, and char.</div>

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