Advertisements I have this simple code snippet as seen below: #include <stdio.h> #include <stdlib.h> int main() { int size; int *a, *a2; size = 5; a = malloc(size * sizeof(int)); if(a == NULL) { fprintf(stderr, "Failure at allocating memory for array.\n"); abort(); } for(int i = 0; i < size; i++) { a[i] = i… Read More Realloc doesn't shrink memory? (C)
Advertisements I’m working on a C program to create an interactive interface for a dynamic array of strings. The program is menu-driven and follows these steps: Asks the user for the initial length of the array. Stores corresponding strings into a dynamic array initialized with that length. Initiates a loop of the menu, prompting the… Read More Value of n sets to 0 or 1 (undefined behavior) while I'm trying to learn use of realloc and malloc
Advertisements I wrote a function to append pointer to an object to array, but realloc can’t properly reallocate memory when it’s called from a nested function. However, when I’m reallocating memory from function, where object has been previously allocated, everything is alright Here is a simplified example of my code: #include <stdlib.h> typedef struct Node… Read More Error during memory reallocation inside a function
Advertisements #include <stdio.h> #include <stdlib.h> int LENGTH = 1; int TOP = -1; void push(char**, char); char pop(char*); char peek(char*); int isEmpty(); int isFull(); void convertToRPN(char*, char*, char*); int isOperator(char); int getPrecedence(char); int main(void) { char* stack = (char*) malloc(sizeof(char) * LENGTH); if (!stack) { printf("Memory allocation failed./n"); exit(1); } char expression[100]; printf("Enter the mathematical… Read More c stack (using dynamic array) realloc memory leak problem
Advertisements I’m Tryng to write a code that have to expand the memory of a malloc array of 1 for some cicles of a loop (i need to store the zeros of a function). but after compiling this error occurs: realloc(): invalid next size Aborted (core dumped) have someone an idea of the reasons of… Read More realloc() : invalid next size Aborted (core dumped)
Advertisements I’m attempting to write a PE parser, and my program contains two loops as shown below: size_t i = 0; while (condition_1) { struct _IMAGE_IMPORT_DESCRIPTOR64 *importDescriptorArray = malloc(sizeof(struct _IMAGE_IMPORT_DESCRIPTOR64)); struct _IMAGE_THUNK_DATA64 *originalFirstThunkArray = malloc(sizeof(struct _IMAGE_THUNK_DATA64)); size_t originalFirstThunkArrayIndex = 0; originalFirstThunkArray[originalFirstThunkArrayIndex].u1.ordinal = some_value; //set to a computed value while (condition_2) { originalFirstThunkArrayIndex++; originalFirstThunkArray = realloc(originalFirstThunkArray,… Read More Undefined Behavior on inner realloc()
Advertisements I am using the editline library to get user input and hand that input to a scanner. The scanner requires any valid input to end with a newline character to unambiguously indicate the end of the last token. However, the input returned by the readline function doesn’t end with a newline character. What is… Read More How do you add a newline to the end of a string in C?
Advertisements How to shrink at runtime a struct matrix (using reallocate() for example) I have a struct matrix which I use to set a vector of size 3 with entries (1,2,3). How is it possible to shrink the size of the vector to retain the 2 first elements and remove the third one (the 3)?… Read More How to shrink at runtime a struct matrix (using realloc() for example)
Advertisements I’m trying to write a dynamic array (dynamic in size and type) in C. First I wrote a function to initialize the array. Input is a enum (TYPE) and according to value of this parameter I allocate memory for corresponding type. This is how I initialize the array: … typedef enum { CHAR, INT,… Read More C dynamic array interrupted by signal SIGSEGV
Advertisements Someone said that using the original malloc()/calloc() pointer as the variable that holds the return value of realloc() is wrong. Here is an example: #include <stdlib.h> int main() { int *malloc_ptr = malloc(5 * sizeof(int)); malloc_ptr = realloc(malloc_ptr, 10 * sizeof(int)); return 0; } Their reasoning was that if realloc() failed it would return… Read More Confusion about using malloc/calloc pointer to hold the return value of realloc