stack

问题 for learning purpose I'm implementing a stack with it's functions in c. I added some small additional functionality to use malloc the first time and try to understand it properly. I wrote a function which is initially creating my stack struct. The return value of the function is a new struct with an already allocate memory. What is the best way to handle a malloc exception in a function which return value should be a struct? Maybe should I design the function different? I'm aware that the

问题 I'm writing a program that reads an Infix notation, converts it to Postfix and then evaluate that Postfix. Here's my program: #include<stdio.h> #include <ctype.h> #define SIZE 50 /* Size of Stack */ char s[SIZE]; int top = -1; /* Global declarations */ push(char elem) { /* Function for PUSH operation */ s[++top] = elem; } char pop() { /* Function for POP operation */ return (s[top--]); } int pr(char elem) { /* Function for precedence */ switch (elem) { case '#': return 0; case '(': return 1;

问题 I'm writing a program that reads an Infix notation, converts it to Postfix and then evaluate that Postfix. Here's my program: #include<stdio.h> #include <ctype.h> #define SIZE 50 /* Size of Stack */ char s[SIZE]; int top = -1; /* Global declarations */ push(char elem) { /* Function for PUSH operation */ s[++top] = elem; } char pop() { /* Function for POP operation */ return (s[top--]); } int pr(char elem) { /* Function for precedence */ switch (elem) { case '#': return 0; case '(': return 1;

问题 Is there any way to retrieve the stack and heap usage in C on Linux? I want to know the amount of memory taken specifically by stack/heap. 回答1: If you know the pid (e.g. 1234) of the process, you could use the pmap 1234 command, which print the memory map. You can also read the /proc/1234/maps file (actually, a textual pseudo-file because it does not exist on disk; its content is lazily synthesized by the kernel). Read proc(5) man page. It is Linux specific, but inspired by /proc file systems

问题 When I create multiple threads from a process, then does each thread have its own stack, or is it that they share the stack of their parent process. What happens when a thread makes a system call? Do threads also maintain their own kernel stack like processes? 回答1: Yes threads have their own stacks and their own kernel stacks (e.g. linux). When a thread makes a system call, you trap into kernel mode (from user mode), you pass the arguments to the kernel, the arguments are checked, the kernel

问题 When I create multiple threads from a process, then does each thread have its own stack, or is it that they share the stack of their parent process. What happens when a thread makes a system call? Do threads also maintain their own kernel stack like processes? 回答1: Yes threads have their own stacks and their own kernel stacks (e.g. linux). When a thread makes a system call, you trap into kernel mode (from user mode), you pass the arguments to the kernel, the arguments are checked, the kernel

问题 Following is the implementation of infix to postfix conversion, it is working fine on my computer, but as I am submitting in on SPOJ it is giving me Runtime error SIGSEGV , I am new to competitive programming and I am unable to handle such type of errors. #include <iostream> #include <stack> #include<string.h> #include<ctype.h> using namespace std; int prec(char ch){ switch(ch){ case '^' : return 3; break; case '*': case '/': return 2; break; case '+': case '-': return 1; break; default:

问题 Each thread has its own stack to store local variables. But stacks are also used to store return addresses when calling a function. In x86 assembly, esp points to the most-recently allocated end of the stack. Today, most CPUs have stack grow negatively. This behavior enables arbitrary code execution by overflowing the buffer and overwriting the saved return address. If the stack was to grow positively, such attacks would not be feasible. Is it safer to have the call stack grow upwards? Why

问题 Each thread has its own stack to store local variables. But stacks are also used to store return addresses when calling a function. In x86 assembly, esp points to the most-recently allocated end of the stack. Today, most CPUs have stack grow negatively. This behavior enables arbitrary code execution by overflowing the buffer and overwriting the saved return address. If the stack was to grow positively, such attacks would not be feasible. Is it safer to have the call stack grow upwards? Why

问题 Each thread has its own stack to store local variables. But stacks are also used to store return addresses when calling a function. In x86 assembly, esp points to the most-recently allocated end of the stack. Today, most CPUs have stack grow negatively. This behavior enables arbitrary code execution by overflowing the buffer and overwriting the saved return address. If the stack was to grow positively, such attacks would not be feasible. Is it safer to have the call stack grow upwards? Why