So I have two problems:
I'm using netbeans to code this.
The first is that the array value that I am setting in c.sArr is getting changed from 7 to some random number, and I can't figure out why.
The second is that when I try to run debug in netbeans, the code gives me a segfault, whereas when i run it normally it doesn't. It gives a segfault at the atoi function.
Whats going on here?
#include <stdio.h>
#include <stdlib.h>
#include "spoonMatrix.c"
int main(int argc, char** argv) {
int iterations;
int argCounter = 0;
int debug = 1;
int i,j,q;
if(argc < 2)
return -1;
if(debug == 1){
for(q=0;q<argc;q++)
printf("%s\n", argv[argCounter++]); //Checking the params
}
argCounter = 1;
iterations = atoi(argv[argCounter++]);
if(debug == 1)
printf("%d", iterations);
for(i=0;i<iterations;i++){
int rows = 0;
int columns = 0;
int m = 0, n, p, elemCount;
int posCount = 0;
int temp;
cm c;
c.row = rows;
c.column = columns;
c.elems = (char*)calloc(rows*columns, sizeof(char));
c.sArr = (int*)calloc(rows*columns, sizeof(int));
rows = atoi(argv[argCounter++]);
columns = atoi(argv[argCounter++]);
for(m=0;m<rows*columns;m++)
{
c.sArr[m] = -2;
//printf("Here");
}
if(debug == 1)
{
printf("Rows : Columns - %d : %d\n", rows, columns);
}
temp = argCounter;
printf("argCounter is: %d\n", argCounter);
for(elemCount = 0 ; argCounter < temp + rows; argCounter++)
{
for(n=0; n<columns; n++, elemCount++)
{
c.elems[elemCount] = argv[argCounter][n];
//if(debug == 1)
// printf("%c\t", c.elems[elemCount]);
if(c.elems[elemCount]== 's' || c.elems[elemCount] == 'S')
{
c.sArr[posCount] = elemCount;
printf("%c\t%d\t%d\t%d\n", c.elems[elemCount], elemCount, c.sArr[posCount++], posCount);
}
}
}
printf("%d\n", c.sArr[0]);
if(debug == 1)
{
for(j=0; j<rows*columns; j++)
{
printf("%c ", c.elems[j]);
}
printf("\n");
for(j=0;j<rows*columns;j++)
{
printf("%d ", c.sArr[j]);
}
}
}
return (EXIT_SUCCESS);
}
and
the other file is:
struct charMat{
int row;
int column;
char* elems;
int* sArr;
};
typedef struct charMat cm;
Coded in the hurry, excuse the weird debugging statements.
Thanks
You aren't allocating (enough) memory:
int rows = 0;
int columns = 0;
c.elems = (char*)calloc(rows*columns, sizeof(char)); // rows * columns is 0
c.sArr = (int*)calloc(rows*columns, sizeof(int)); // rows * columns is 0
rows = atoi(argv[argCounter++]);
columns = atoi(argv[argCounter++]);
From calloc:
If the size of the space requested is 0, the behavior is
implementation-defined: the value returned shall be either a null
pointer or a unique pointer.
Related
I am getting the error variable sized object may not be initialized and I don't understand why.
Could someone show me how to fix this line?
int arr[size] = (int *)(augs->one);
Here is my code:
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>
#include <assert.h>
int count = 0;
int cmpfunc(const void *a, const void *b) {
return (*(int*)a - *(int*)b);
}
struct structure {
int two;
int *one;
};
void *sort(void *augments) {
struct structure *augs = (struct structure*)augments;
int i = 0;
int size = 1;
size = augs->two;
int arr[size] = (int *)(augs->one);
//int *arr = (int *)data;
//printf("sizeof:%d\n", sizeof(arr));
qsort(arr, size, sizeof(int), cmpfunc);
printf("finaloutput:\n");
for (i = 0; i < size; i++) {
printf("%d ", arr[i]);
}
printf("\n");
return NULL;
}
int main(int argc, char *argv[]) {
FILE *myFile;
myFile = fopen("data.txt", "r");
// number of lines in file
char charicter;
for (charicter = getc(myFile); charicter != EOF; charicter = getc(myFile)) {
if (charicter == '\n') {
count++;
}
}
printf("count is %d\n", count);
int numberArray[count];
int i = 0;
if ((myFile = fopen("data.txt", "r"))) {
while ((fscanf(myFile, "%d", &numberArray[i]) != EOF)) {
++i;
}
fclose(myFile);
}
assert(argv[1] != NULL);
int num = atoi(argv[1]); //num equals number input
int arrayarray[num - 1][(count / num)];
int idx;
for (i = 0; i < (count); i++) {
printf("numberarray[%d]= %d\n", i, numberArray[i] /*[0],numberArray[i][1]*/);
}
for (i = 1; i < num + 1; i++) {
for (idx = 0; idx < (count / num); idx++) {
arrayarray[i - 1][idx] = numberArray[i * idx];
}
}
///*
for (i = 0; i < ((count / num)); i++) {
printf("arrayarray[0]=%d\n", arrayarray[0][i]);
}
//*/
int lastarray[((count / num) + (count % num))];
for (idx = 0; idx < ((count / num) + (count % num)); idx++) {
lastarray[idx] = numberArray[idx + ((count / num) * (num - 1))];
}
for (i = 0; i < ((((count / num) + (count % num)))); i++) {
printf("lastaray[%d]=%d\n", i, lastarray[i]);
}
//*******************
pthread_t thread_id_arr[num];
for (i = 0; i < num; i++) {
pthread_t tid;
struct structure *augs;
if (i != (num - 1)) {
augs = malloc(sizeof(struct structure) + sizeof(int) + sizeof(int) * num);
(*augs).one = arrayarray[i];
(*augs).two = (count / num);
pthread_create(&tid, NULL, sort, augs);
} else {
(*augs).one = lastarray;
(*augs).two = (count / num) + (count % num);
pthread_create(&tid, NULL, sort, augs);
//pthread_create(&tid, NULL, sort, (void*)lastarray);
}
thread_id_arr[i] = tid;
}
for (i = 0; i < num; i++) {
pthread_join(thread_id_arr[i], NULL);
}
return 0;
}
As others pointed out, you can't initialize a Variable Length Array with a pointer, like you are doing. However, you don't actually need a VLA at all. Use this instead :
int *arr = augs -> one;
You want to act directly on the array that is passed into the thread, not make a copy of it.
That being said, I see another problem. In the loop that spawns the sorting threads, you are not allocating a new args on the last loop iteration, it reuses the allocated args from the previous iteration, which can cause disaster for the 2nd-to-last thread. You need to move the malloc() call above the if.
Also, the malloc() is allocating more memory than your threads actually use. You only need to allocate enough memory for just the struct by itself, not for any integers following the struct.
Also, when each thread is done using the allocated args that it is given, it needs to free() the args to avoid leaking memory.
I have to create a program for an assignment that solves a sudoku puzzle. User needs to enter the name of a binary file (NOT a true binary file, it just has a .bin extension, it can be opened with notepad, notepad++ etc. as well) that contains numbers. Those numbers represent coordinates on the puzzle as well as the number contained in those coordinates e.g 432 means 4th row 3rd column contains number 2. After filling out the puzzle i need to solve it and print it on screen. After executing the program it crashed, so I decided to use MSVC 2017 debugger which is among the best according to some developers to find and fix the bug. Here is my code:
Sudoku.c
#include <stdio.h>
#include <stdlib.h>
#include "stdafx.h"
#include "sudokulib.h"
#define MALLOC_ERROR 0xFF
#define FILE_NOT_FOUND 0xFFF
#define ROWS 9
#define COLUMNS 9
int main(int argc, char ** argv)
{
char **matrix;
int i, args;
int row, column, num;
FILE * fp;
char * filename;
char * importedData;
matrix = (char **)malloc(ROWS * sizeof(char *));
if (!matrix)
exit(MALLOC_ERROR);
for (i = 0; i<ROWS; ++i)
{
matrix[i] = (char *)malloc(COLUMNS * sizeof(char));
if (!matrix[i])
exit(MALLOC_ERROR);
}
initSudoku(matrix);
printf ("Give me the name of data file: ");
filename = (char *)malloc(100 * sizeof(char));
if (!filename)
exit(MALLOC_ERROR);
scanf("%99s", filename);
fp = fopen(filename, "rb");
if (!fp)
{
printf ("File not found\n");
exit(FILE_NOT_FOUND);
}
importedData = (char *)malloc(sizeof(char)*ROWS*COLUMNS * 3);
if (!importedData)
exit (MALLOC_ERROR);
args = fread(importedData, 1, 243, fp);
i = 0;
while (importedData[i] != ' ' && importedData[i + 1] != ' ' && importedData[i + 2] != ' ' && importedData[i] >= '1' && importedData[i + 1] >= '1' && importedData[i + 2] >= '1' && importedData[i] <= '9' && importedData[i + 1] <= '9' && importedData[i + 2] <= '9' && i < 243)
{
row = importedData[i] - '0' - 1; /* Convert from ascii code to number */
column = importedData[i + 1] - '0' - 1;
num = importedData[i + 2] - '0';
matrix[row][column] = num;
i = i + 3;
}
printf("Sudoku after importing data:\n\n");
printSudoku(matrix);
system("pause");
if (solvePuzzle(matrix))
{
printSudoku(matrix);
}
else
printf ("Puzzle has no solution\n");
fclose(fp);
free(filename);
for (i = 0; i<9; ++i)
{
free(matrix[i]);
}
free(matrix);
return 0;
}
Sudokulib.h
#pragma once
#include <stdlib.h>
#include <stdio.h>
/* Function Prototypes Begin Here */
void printSudoku(char **);
void initSudoku(char **);
int checkRow(char **, int, int);
int checkCol(char **, int, int);
int check3x3(char **, int, int, int);
int checkIfEmpty(char **, int*, int*);
int solvePuzzle (char **);
/* Function Prototypes End Here */
void printSudoku(char ** Mat)
{
int i, j;
for (i = 0; i<9; ++i)
{
printf ("-------------------\n");
printf("|");
for (j = 0; j<9; ++j)
{
printf("%d|", Mat[i][j]);
}
printf("\n");
}
printf ("-------------------\n");
}
void initSudoku(char ** Mat)
{
int i, j;
for (i = 0; i<9; ++i)
for (j = 0; j<9; ++j)
Mat[i][j] = 0;
}
int checkRow (char ** Mat, int row, int num) // if row is free returns 1 else returns 0
{
int col;
for (col = 0; col < 9; col++)
{
if (Mat[row][col] == num)
{
return 0;
}
}
return 1;
}
int checkCol (char ** Mat, int col, int num) // if column is free returns 1 else returns 0
{
int row;
for (row = 0; row < 9; row++)
{
if (Mat[row][col] == num)
{
return 0;
}
}
return 1;
}
int check3x3 (char ** Mat, int row, int col, int num) // if number doesnt exist in the 3x3 grid returns 1 else returns 0
{
row = (row / 3) * 3; // set to first row in the grid
col = (col / 3) * 3; // set to first col in the grid
int i;
int j;
for (i = 0; i < 3; i++) // grid is 3x3
{
for (j = 0; j < 3; j++)
{
if (Mat[row + i][col + j] == num)
{
return 0;
}
}
}
return 1;
}
int isValid (char ** Mat, int row, int col, int num)
{
return (checkRow(Mat, row, num) && checkCol(Mat, col, num) && check3x3(Mat, row, col, num));
}
int checkIfPuzzleSolved (char ** Mat, int *row, int *col) // if function finds a box empty (puzzle not solved) returns 0 else returns 1
{
for (*row = 0; *row < 9; *row++)
{
for (*col = 0; *col < 9; *col++)
{
printf("ROW: %d COL: %d\n",*row,*col);
if (Mat[*row][*col] == 0)
{
return 0;
}
}
}
return 1;
}
int solvePuzzle (char ** Mat)
{
int row;
int col;
if (checkIfPuzzleSolved(Mat, &row, &col))
{
return 1;
}
int num;
for (num = 1; num <= 9; num++)
{
//if (checkRow (Mat,row,num) && checkCol (Mat,col,num) && check3x3 (Mat,row,col,num))
if (isValid(Mat, row, col, num))
{
Mat[row][col] = num;
if (solvePuzzle(Mat))
return 1;
Mat[row][col] = 0;
}
}
return 0;
}
The debugger found a bug at this function:
int checkIfPuzzleSolved (char ** Mat, int *row, int *col) // if function finds a box empty (puzzle not solved) returns 0 else returns 1
{
for (*row = 0; *row < 9; *row++)
{
for (*col = 0; *col < 9; *col++)
{
printf("ROW: %d COL: %d\n",*row,*col);
if (Mat[*row][*col] == 0) /* DEBUGGER ERROR CODE 0xC0000005: Access violation reading location 0xCDCA247C
{
return 0;
}
}
}
return 1;
}
Two things that confused me:
1) I don't understand the reason solvePuzzle gets stuck brute forcing the first box in the puzzle (1st row 1st column). It seems that checkIfPuzzleSolved thinks that the first box is empty (containing 0), even though using printSudoku I can see the algorithm modifying that box toggles its value between 3 and 4 and obviously 0 != 3 and 0 != 4.
2) In checkIfPuzzleSolved, printf prints on screen row and column number and it constantly produces the following result:
ROW: 0 COL: 0
ROW: 0 COL: 0
ROW: 0 COL: -858993460
Also double checked this with the debugger and the values are indeed those mentioned.
My train of thought was the following:
1) Use checkIfEmpty to determine if a box of the puzzle contained 0, that would mean that the puzzle would not be solved yet. Row and col variables are sent into the function by reference, so when function finds an empty box and returns, row and col would save the coordinates of the empty box.
2) In the loop, call checkRow, checkCol and check3x3 to check if a number can be put into the desired box without breaking the sudoku rules. isValid is there for readability purposes.
3) Call solvePuzzle recursively until the puzzle is solved, meanwhile if a number is wrong, reset it to 0.
I have tried everything i could think of to solve this problem, wasting hours reading again and again my code to find a logical error, but everything seems okay. Any ideas?
EDIT: On request of Michael Beer, here is a sample binary file:
data.bin
142156177191216228257289311329364375418422441484534546562579625663682698739743787794824855883896917933951968
*row++; parses as *(row++);, which is equivalent to just row++. You're incrementing the pointer, not the counter.
– melpomene
I see. So am I incrementing the pointer by sizeof(int) and not increasing the value that it refers to by 1? If so what is the correct way of writing "increment the value of the address you are pointing to by 1" regarding the syntax?
(*row)++ or ++(*row) or ++*row or *row += 1.
– melpomene
I'm trying to write Conway's game of life in C. This is what I have so far. I'm using pointers to refer to the arrays, which has never caused me problems before, but the function place_cell is causing a segfault.
Here's what I've tried so far:
- I tried making the grid with constants, 100 x 100, and 10 x 10. Modifying
values inside of those constant grids still gives me a segfault.
- I tried using constants for place_cell, still got a segfault.
int** make_grid(int x, int y) {
int** is = (int**)malloc(sizeof(int*) * y);
if(! is) {
fprintf(stderr, "make_grid: malloc failed");
exit(1);
}
int j;
for(j = 0; j < y; j++) {
is[j] = (int*)malloc(sizeof(int) * x);
if(!is[j]) {
fprintf(stderr, "make_grid: malloc failed");
exit(1);
}
}
return is;
}
/* takes two integers and places a cell at those coords */
void place_cell(int** is, int sidex, int sidey, int x, int y) {
if(x >= sidex || y >= sidey) {
fprintf(stderr, "place_cell: out of grid range\n");
exit(1);
}
is[y][x] = 1;
}
int check_surroundings(int** is, int sidex,
int sidey, int x, int y) {
int y_less = y - 1;
if(y == 0) {
y_less = sidey - 1;
}
int y_more = y + 1;
if(y == sidey - 1) {
y_more = 0;
}
int x_less = x - 1;
if(x == 0) {
x_less = sidex - 1;
}
int x_more = x + 1;
if(x == sidex - 1) {
x_more = 0;
}
int p = is[y_less][x_less] +
is[y_less][x] +
is[y_less][x_more] +
is[y][x_less] +
is[y][x_more] +
is[y_more][x_less] +
is[y_more][x_less] +
is[y_more][x_more];
return p;
}
void change_condition(int** is,
int sidex, int sidey, int x, int y) {
int* state = &is[y][x];
int surr = check_surroundings(is, sidex, sidey, x, y);
if(surr > 3) {
*state = 0;
} else if(surr == 3 || surr == 2) {
*state = 1;
} else {
*state = 0;
}
}
void print_grid(int** is, int sidex, int sidey) {
int i, j;
for(i = 0; i < sidey; i++) {
for(j = 0; j < sidex; j++) {
if(is[i][j] == 1) {
printf("*");
} else {
printf(" ");
}
}
printf("\n");
}
}
void new_generation(int** is, int sidex, int sidey) {
int i, j;
for(i = 0; i < sidey; i++) {
for(j = 0; j < sidex; j++) {
change_condition(is, sidex, sidey, j, i);
}
}
}
void play(int** is, int sidex, int sidey) {
int i = 0;
while(i < 100) {
new_generation(is, sidex, sidey);
print_grid(is, sidex, sidey);
i++;
}
}
here's my main:
int main(int argc, char* argv[]) {
int sidex = atoi(argv[0]);
int sidey = atoi(argv[1]);
int** is = make_grid(10, 10);
int i;
for(i = 2; i < argc; i += 2) {
place_cell(is, sidex, sidey,
atoi(argv[i]), atoi(argv[i + 1]));
}
return 0;
}
edit:
int** make_grid(int x, int y) {
int (*is)[x] = (int*)malloc(sizeof(int) * y * x);
if(! is) {
fprintf(stderr, "make_grid: malloc failed");
exit(1);
}
int j;
for(j = 0; j < y; j++) {
is[j] = (int*)malloc(sizeof(int) * x);
if(!is[j]) {
fprintf(stderr, "make_grid: malloc failed");
exit(1);
}
}
return is;
}
This isn't right at all but I can't put my finger on why. Can someone explain to me what to change like I'm five? (a five year-old who knows C, I guess)
I just copied your entire code and tried to run the program. The memory access violation (at least for me) is in this line:
int sidex = atoi(argv[0]);
int sidey = atoi(argv[1]); <-- memory access violation
The reason is (in my case at least) that I just ran the program with no arguments.
Now, even if I did provide the arguments on the command line the indexing is still off. The first argument argv[0] is the name of the executable, not the first argument after the name.
So, a few things to note for your code:
It is not guaranteed that there will be arguments. You should always check the argc to make sure you can index into argv
Those arguments are not guaranteed to be integer numbers either - you better check for that too, before you use them as your dimensions
Of course with the indexing shift you should adjust for your "array reading" code accordingly as well. But once you fix the indexing this should be an easy one for you
You are not declaring a two-dimensional array with that syntax, so the memory is not aligned the way you think, thus a segmentation fault. Declaring a pointer int** does not make it a 2-D array. (Surely you don't think int *** would get you a data cube ?).
Heap allocate a 2D array (not array of pointers)
One of the comments above gives the other problem, the zero parameter to a C program argv[0] is the name of the program, not the first parameter on the command line, that is argv[1].
I have a problem with dynamic arrays in C. My program was working perfectly, but I was asked to put the creation of dynamic array into a seperate void. I did it, and it still worked great, but then I had to assign a value to a certain point of the created array in void, and make it return the said value, however, what I get is a random value. The function works by sending a pointer and the lenght of required array into void, and then makes the pointer into a dynamic array.
#include <stdio.h>
#include <stdlib.h>
#define MAX 255
void ieskom (int skaiciai[],int n, int *de, int *me, int *n1, int *n2)
{
int i = 0;
int j = 0;
int nr1 = 0;
int nr2 = 0;
int temp = 0;
int temp1 = 0;
int eile = 0;
int eile1 = 0;
int *did;
did = (int*)calloc(n,sizeof(int));
if (did==NULL)
{
printf("Nepriskirta atminties.");
exit(0);
}
int *maz;
maz = (int*)calloc(n,sizeof(int));
if (maz==NULL)
{
printf("Nepriskirta atminties.");
exit(0);
}
i = 0;
for (i = 0; i < n; i++)
{
if (skaiciai[i] < skaiciai[i+1])
{
did[j] = did[j] + 1;
if (did[j] > temp)
{
eile = j;
temp = did[j];
nr1 = i+1;
}
}
else
{
did[j] = did[j] + 1;
if (did[j] > temp)
{
eile = j;
temp = did[j];
nr1 = i+1;
}
j = j + 1;
}
}
j = 0;
for (i = 0; i < n; i++)
{
if (skaiciai[i] > skaiciai[i+1])
{
maz[j] = maz[j] + 1;
if (maz[j] > temp1)
{
eile1 = j;
temp1 = maz[j];
nr2 = i+1;
}
}
else
{
maz[j] = maz[j] + 1;
if (maz[j] > temp1)
{
eile1 = j;
temp1 = maz[j];
nr2 = i+1;
}
j = j + 1;
}
}
*de = did[eile];
*me = maz[eile1];
*n1 = nr1;
*n2 = nr2;
free(did);
free(maz);
}
/*int masyvas(x)
{
int y;
y = (int*)malloc(x*sizeof(int));
return y;
}*/
void *masyvas (int *skaiciai, int n)
{
*skaiciai = (int*)malloc(n*sizeof(int));
skaiciai[2] = 5;
return skaiciai;
}
int main()
{
int n1 = 0;
int n2 = 0;
int de = 0;
int me = 0;
int i = 0;
int n = 0;
int *skaiciai;
scanf("%d", &n);
// skaiciai = masyvas(n); // naudojant int
masyvas(&skaiciai, n);
printf("2 = %d", skaiciai[2]);
if (skaiciai==NULL)
{
printf("Nepriskirta atminties.");
exit(0);
}
for (;i < n; i++)
{
scanf("%d", &skaiciai[i]);
}
ieskom (skaiciai, n, &de, &me, &n1, &n2);
if (de > me)
{
printf("Elementu numeriai:");
printf(" %d", n1-de+1);
printf(" %d\n", n1);
printf("\nAtstumas tarp ju: %d", de-2);
}
else
{
printf("Elementu numeriai:");
printf(" %d", n2-me+1);
printf(" %d\n", n2);
printf("\nAtstumas tarp ju: %d", me-2);
}
free(skaiciai);
getchar();
getchar();
return 0;
}
The problem is in void masyvas and printf skaicia[2] - I assign a certain value to skaiciai[2], yet it prints a random one. How do I fix it?
EDIT: Thank you for your answers and explanations, it really helped me a lot! I know have solved my problem, and most importantly, I know why it was a problem in the first place.
First of all, you should translate variables and texts to english (your code lack of comments, this should apply to them too).
Next your masyvas() function returns a pointer to the allocated array (why void* ?!) but when you call it you don't get the returned value.
You have to choose: either you pass a pointer to your function (an array is a pointer, to if you want an array to be allocated from a function you have to pass a pointer to the pointer, so a int **), or you use the returned value.
Allocating with returned value:
// this function allocates a int* tab of size n and set one value
int *allocate_tab(int n) {
int *tmp;
tmp = malloc(n*sizeof(int));
if (tmp == NULL) {
return(NULL); // failed
}
tmp[2] = 5;
return(tmp);
}
// in main (or other function)
int *mytab;
mytab = alloc_tab(45);
Allocating by passing a pointer to the array:
void alloc_tab(int **tab, int n) {
*tab = malloc(n*sizeof(int));
if (*tab == NULL) {
return;
}
(*tab)[2] = 5;
}
// in main (or other)
int *mytab;
alloc_tab(&mytab, 45);
If you can't understand this stuff I guess you should read more about memory, allocation and pointers.
You need to pass a pointer-to-pointer here and do not need to return anything.
void masyvas (int **skaiciai, int n)
{
*skaiciai = (int*)malloc(n*sizeof(int));
(*skaiciai)[2] = 5;
}
When you declare int *skaiciai, the variable is a pointer to type int. skaiciai holds the address that points to an int. When you pass &skaiciai, you're passing the address of the address that points to an int. So because this is an address of an address, its a double pointer.
Hi Guys i have edited the questions.Here is my entire code.I have given basic amount of readability to my program.I hope u guys can understand the program.
#include<stdio.h>
#include<stdlib.h>
int Max_Min(int,int,int,int *, int *);
int *Max,Number;
int main()
{
int n1, n2,Maximum_Element=0,*Max;
int i = 0, j = 0;
scanf("%d",&Number);
Max =(int *) malloc(sizeof(int)*Number);//Array Max is created
for (int k = 0;k <(Number/2);k++)
{
scanf("%d", &n1);
scanf("%d", &n2);
Max[k] = Max_Min(0,1,0,&n1,&n2);//Passing integer elements n1,n2 with flag 0
}
Maximum_Element=Max_Min(1,1,((sizeof(Max)*Number)/8),Max,Min);//Passing array elements Max,Min with flag 1 to function Max_Min
printf("Maximum_Element=%d", Maximum_Element);
return 0;
}
int Max_Min(int flag,int Max_Min_flag,int length,int *n1,int *n2)//n1 and n2 should be able to handle array and integers
{
int i=0,j = 0,k1,k2,Min1 = 0, Min2 = 0,count=0, Not_Zero = 0,x=0,y=0, *New_Max = 0,*New_Min;
/*Recursive Loop for splitting the array elements and calling the array */
if (flag == 1)
{
New_Max = (int *)(malloc(sizeof(int)*length));
for (;i <= ((length) / 2);i = i + 2)//
{
k1 = n1[i];
j = i + 1;
if (j <= ((length + 1) / 2))
{
k2 = n1[j];
New_Max[count] = Max_Min(0, 1, 0, &k1, &k2);//It is passing integer elements with flag 0 to function Max_Min
count++;
}
}
New_Max[count] = n1[j + 1];
for (int i = 0;i < count + 1;i++)
{
**/* Problem is assigning Max[i]=New_Max[i] is not getting assigned*/**
Max[i] = New_Max[i];//Copying from New_Max to Max because New_Max will be overwritten,so possible chaunce of dataloss
Not_Zero++;
}
while ((sizeof(Max) / 4 - (Not_Zero))>0)
{
Max[Not_Zero] = 0;
Not_Zero++;
}
/*Logic for calling recursive functions based on the count*/
if (count > 1)
{
count--;
Max_Min(1, 1, count, Max, Min);//Calling Recursive function by Passing Entire Arrays with flag 1.
}
else if (count == 1 && Max[1] == 0)
{
*n1 = Max[0];
*n2 = Min[0];
}
else if (count == 1 && Max[2] == 0)
{
Max_Min(1, 1, count + 1, Max, Min);
count--;
}
}
/*Logic for Finding Maximum & Minimum element is present down*/
if (flag == 0)
{
printf("flag");
if (Max_Min_flag == 1)
{
if (*n1 > *n2)
{
}
else if ((*n1 < *n2) && Max_Min_flag == 1)
{
int temp = 0;
temp = *n1;//5
*n1 = *n2;//7
*n2 = temp;//5
}
}
else if (Max_Min_flag == 2)
{
if (*n1 > *n2)//7>2
{
int temp = 0;
temp = *n1;//2
*n1 = *n2;//2
*n2 = temp;//2,7
}
else if (*n1 < *n2)
{
}
}
}
return *n1;//7
}
Problem is assigning Max[i]=New_Max[i] in function Max_Min().It shows Run time error as "Access violation writing location 0x00000000."
First you need to #include <stdlib.h> to use malloc
You must declare your function before using it.
func must return int*.
Also in func "n", first "Max", and second "Max" needs to be the same variable. Rename "n" to "Max"
This is the code corrected with an extra printf;
#include <stdio.h>
#include <stdlib.h>
int *Max,Number=5;
int* func(int *Max)
{
for(int j=0;j<5;j++)
Max[j]=j;//Its not working in this line
return Max;
}
int main()
{
Max=(int *) malloc(sizeof(int)*Number);
for(int i=0;i<5;i++)
Max[i]=i;
int* x = func(Max);
for(int i=0;i<5;i++)
printf("%d", x[i]);
}
The following contains only minor adaptations of your code and it runs fine:
int *func(int *n);
int *Max,Number=5;
int main()
{
int *x,i;
Max=(int *) malloc(sizeof(int)*Number);
for(i=0;i<Number;i++)
Max[i]=i;
x=func(Max);
free(Max);
return(0);
}
int *func(int *n)
{
int j;
for (j=0;j<Number;j++)
n[j]=Number-j; // reverse the number, just to check
return Max;
}