I'm trying to create an array (dynamically) and populate it with random numbers.
I'm on Linux. The program compiles without errors. This is the C code:
#include <stdio.h> #include <stdlib.h> #include <time.h> void create_array(int **, int); void populate_array(int *X, int size, int low, int high); void display_array(int *X, int size); int main() { int *A = NULL; int size = 7; int low = 10; int high = 1000; create_array(&A, size); populate_array(A, size, low, high); display_array(A, size); return 0; } void create_array(int **X, int size) { *X = (int *)(malloc(size)); } void populate_array(int *X, int size, int low, int high) { srand(time(0)); for (int i = 0; i < size; ++i) { *(X + i) = low + rand() % (high + 1 - low); } } void display_array(int *X, int size) { for (int i = 0; i < size; ++i) { if (i % 10 == 0) printf("\n"); printf("%d\t", *(X + i)); } printf("\n"); } However, when I run it, I get the following error:
malloc.c:2394: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed. Aborted (core dumped)
This error is only produced for size = 7. For lower values it's all good. But for higher values, it's another story! Output for size = 20:
455 526 335 719 907 695 1041 0 154481972 154546741 154481459 154743095 154482992 875836721 960049720 926419250 909326389 154219063 808465977 842479924 In contrast, the same program (almost) in C++ gives me the expected output. Here's the code:
#include <iostream> #include <cstdlib> #include <ctime> using namespace std; void create_array(int *&, int); void populate_array(int *X, int size, int low, int high); void display_array(int *X, int size); int main() { int *A; int size = 100; int low = 10; int high = 1000; create_array(A, size); populate_array(A, size, low, high); display_array(A, size); return 0; } void create_array(int *&X, int size) { X = new int[size]; } void populate_array(int *X, int size, int low, int high) { srand(time(0)); for (int i = 0; i < size; ++i) { X[i] = low + rand() % (high + 1 - low); } } void display_array(int *X, int size) { for (int i = 0; i < size; ++i) { if (i % 10 == 0) cout << endl; cout << X[i] << "\t"; } cout << endl; } What am I doing wrong?
