#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
|
|
void displayArray(int arr[], size_t size);
|
|
void displayArrayPtr(int *arr, size_t size);
|
|
int safeCompare(const void *a, const void *b, size_t asize, size_t bsize);
|
|
int valid(void *p);
|
|
void display2DArray(int arr[][5], size_t rows);
|
|
void display2DArrayPtr(int (*arr)[5], size_t rows);
|
|
void display2DArrayUnknownSize(int *arr, size_t rows, size_t cols);
|
|
void display3DArrayPtr(int (*arr)[2][4], size_t rows);
|
|
|
|
|
|
void displayArray(int arr[], size_t size) {
|
|
for (size_t i = 0; i < size; i++) {
|
|
// both variants are possible
|
|
printf("%d\n", arr[i]);
|
|
//printf("%d\n", *(arr + i));
|
|
}
|
|
}
|
|
|
|
|
|
void displayArrayPtr(int *arr, size_t size) {
|
|
for (size_t i = 0; i < size; i++) {
|
|
// both variants are possible
|
|
printf("%d\n", *(arr + i));
|
|
//printf("%d\n", arr[i]);
|
|
}
|
|
}
|
|
|
|
|
|
int safeCompare(const void *a, const void *b, size_t asize, size_t bsize) {
|
|
if (asize != bsize) {
|
|
return -1;
|
|
}
|
|
int value = 0;
|
|
for (size_t i = 0; i < asize; i++) {
|
|
//value |= a[i] ^ b[i];
|
|
value |= ((unsigned char*) a)[i] ^ ((unsigned char*) b)[i];
|
|
}
|
|
return value;
|
|
}
|
|
|
|
|
|
void display2DArray(int arr[][5], size_t rows) {
|
|
for (size_t i = 0; i < rows; i++) {
|
|
for (size_t j = 0; j < 5; j++) {
|
|
printf("%d", arr[i][j]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
|
|
|
|
void display2DArrayPtr(int (*arr)[5], size_t rows) {
|
|
for (size_t i = 0; i < rows; i++) {
|
|
for (size_t j = 0; j < 5; j++) {
|
|
printf("%d", *(arr[i] + j));
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
|
|
|
|
void display2DArrayUnknownSize(int *arr, size_t rows, size_t cols) {
|
|
for (size_t i = 0; i < rows; i++) {
|
|
for (size_t j = 0; j < cols; j++) {
|
|
// both are equivalent
|
|
//printf("%d", *(arr + (i * cols) + j));
|
|
printf("%d", (arr + (i * cols))[j]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
|
|
|
|
void display3DArrayPtr(int (*arr)[2][4], size_t rows) {
|
|
for (size_t i = 0; i < rows; i++) {
|
|
for (size_t j = 0; j < 2; j++) {
|
|
printf("{");
|
|
for (size_t k = 0; k < 4; k++) {
|
|
printf("%d", arr[i][j][k]);
|
|
if (k != 3) {
|
|
printf(" ");
|
|
}
|
|
}
|
|
printf("}");
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
|
|
|
|
int main(void) {
|
|
|
|
int vector[5] = {1,2,3,4,5};
|
|
|
|
printf("length of vector: %zu\n", sizeof(vector)/sizeof(int));
|
|
|
|
int matrix[2][3] = {{1,2,3},{4,5,6}};
|
|
|
|
for (size_t index = 0; index < 2; index++) {
|
|
printf("&matrix[%zu]: %p sizeof(matrix[%zu]): %zu\n",
|
|
index, &matrix[index], index, sizeof(matrix[index]));
|
|
}
|
|
|
|
// pointer notation and arrays
|
|
{
|
|
int *pv = vector;
|
|
int value = 3;
|
|
for (size_t index = 0; index < sizeof(vector)/sizeof(int); index++) {
|
|
// all following operations are equivalent
|
|
*pv++ *= value;
|
|
//pv[index] *= value;
|
|
//*(pv + index) *= value;
|
|
//vector[index] *= value;
|
|
}
|
|
for (size_t index = 0; index < sizeof(vector)/sizeof(int); index++) {
|
|
printf("vector[%zu]: %d\n", index, vector[index]);
|
|
}
|
|
}
|
|
|
|
// using malloc to create a one-dimensional array
|
|
{
|
|
int *pv = malloc(5 * sizeof(*pv));
|
|
for (size_t i = 0; i < 5; i++) {
|
|
pv[i] = i + 1;
|
|
}
|
|
for (size_t i = 0; i < 5; ++i) {
|
|
*(pv + i) = i + 1;
|
|
}
|
|
for(size_t index = 0; index < 5; index++) {
|
|
printf("pv[%zu]: %d\n", index, pv[index]);
|
|
}
|
|
free(pv);
|
|
}
|
|
|
|
// passing array to function using array notation
|
|
displayArray(vector, sizeof(vector)/sizeof(int));
|
|
|
|
// passing array to function using pointer notation
|
|
displayArrayPtr(vector, sizeof(vector)/sizeof(int));
|
|
|
|
|
|
// using a one-dimensional array of pointers
|
|
{
|
|
int *arr[5];
|
|
for (size_t i = 0; i < 5; i++) {
|
|
// both variants are equivalent
|
|
arr[i] = malloc(sizeof(arr[i]));
|
|
*arr[i] = i;
|
|
//arr[i][0] = i;
|
|
//*(arr + i) = (int*) malloc(sizeof(int));
|
|
//**(arr + i) = i;
|
|
printf("%d\n", **(arr + i));
|
|
}
|
|
for (size_t i = 0; i < 5; i++) {
|
|
free(arr[i]);
|
|
}
|
|
}
|
|
|
|
|
|
// pointers and multidimensional arrays
|
|
{
|
|
// declare a 2-dimensional array
|
|
int matrix[2][5] = {{1, 2, 3, 4, 5}, {6, 7, 8, 9, 10}};
|
|
for (size_t i = 0; i < 2; i++) {
|
|
for (size_t j = 0; j < 5; j++) {
|
|
printf("matrix[%zu][%zu] Address: %p Value %d\n", i, j, &matrix[i][j], matrix[i][j]);
|
|
}
|
|
}
|
|
// declare a pointer to a 2-dimensional array
|
|
int (*pmatrix)[5] = matrix;
|
|
|
|
// 1st row
|
|
printf("%p\n", matrix);
|
|
// 2nd row
|
|
printf("%p\n", matrix + 1);
|
|
// size of 1st row
|
|
printf("sizeof(matrix[0]): %zu\n", sizeof(matrix[0]));
|
|
// access 2nd element
|
|
printf("%p %d\n", matrix[0] + 1, *(matrix[0] + 1));
|
|
}
|
|
|
|
|
|
// passing a multidimensional array
|
|
{
|
|
// declare a 2-dimensional array
|
|
int matrix[2][5] = {{1, 2, 3, 4, 5}, {6, 7, 8, 9, 10}};
|
|
|
|
display2DArray(matrix, 2);
|
|
display2DArrayPtr(matrix, 2);
|
|
display2DArrayUnknownSize(&matrix[0][0],
|
|
sizeof(matrix) / sizeof(matrix[0]),
|
|
sizeof(matrix[0]) / sizeof(*matrix[0]));
|
|
|
|
int arr3D[][2][4] = {
|
|
{{1, 2, 3, 4}, {5, 6, 7, 8}},
|
|
{{9, 10, 11, 12}, {13, 14, 15, 16}},
|
|
{{17, 18, 19, 20}, {21, 22, 23, 24}}
|
|
};
|
|
display3DArrayPtr(arr3D, 3);
|
|
}
|
|
|
|
|
|
// dynamically allocating a two-dimensional array
|
|
{
|
|
// allocating contigously memory
|
|
int matrix[2][5] = {{1, 2, 3, 4, 6}, {6, 7, 8, 9, 10}};
|
|
|
|
for (size_t i = 0; i < 2; i++) {
|
|
for (size_t j = 0; j < 5; j++) {
|
|
printf("matrix[%zu][%zu] Address: %p Value: %d\n", i, j, &matrix[i][j], matrix[i][j]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
// allocating potential noncontiguous memory
|
|
{
|
|
size_t rows = 2;
|
|
size_t cols = 5;
|
|
|
|
int **matrix = malloc(rows * sizeof(int *));
|
|
|
|
for (size_t i = 0; i < rows; i++) {
|
|
matrix[i] = malloc(cols * sizeof(int));
|
|
}
|
|
|
|
free(matrix);
|
|
}
|
|
|
|
// allocating contiguous memory
|
|
{
|
|
size_t rows = 2;
|
|
size_t cols = 5;
|
|
|
|
int **matrix = malloc(rows * sizeof(int*));
|
|
|
|
matrix[0] = malloc(rows * cols * sizeof(int));
|
|
|
|
for (size_t i = 1; i < rows; i++) {
|
|
matrix[i] = matrix[0] + i * cols;
|
|
}
|
|
|
|
free(matrix);
|
|
}
|
|
|
|
// allocating contiguous memory
|
|
{
|
|
size_t rows = 2;
|
|
size_t cols = 5;
|
|
|
|
int *matrix = malloc(rows * cols * sizeof(int));
|
|
|
|
for (size_t i = 0; i < rows; i++) {
|
|
for (size_t j = 0; j < cols; j++) {
|
|
*(matrix + (i * cols) + j) = i * j;
|
|
}
|
|
}
|
|
|
|
free(matrix);
|
|
}
|
|
|
|
// jagged arrays and pointers
|
|
{
|
|
// 2 dimensional array with compound literals
|
|
int *arr1[] = {
|
|
(int[]) {0, 1, 2},
|
|
(int[]) {3, 4, 5},
|
|
(int[]) {6, 7, 8}
|
|
};
|
|
|
|
for (size_t i = 0; i < 3; i++) {
|
|
for (size_t j = 0; j < 3; j++) {
|
|
printf("arr1[%zu][%zu] Address: %p Value: %d\n", i, j, &arr1[i][j], arr1[i][j]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
// 2 dimensinal jagged array with compound literals
|
|
int *arr2[] = {
|
|
(int[]) {0, 1, 2, 3},
|
|
(int[]) {4, 5},
|
|
(int[]) {6, 7, 8}
|
|
};
|
|
|
|
for (size_t i = 0; i < 4; i++) {
|
|
printf("arr2[0][%zu] Address: %p Value: %d\n", i, &arr2[0][i], *(arr2[0] + i));
|
|
}
|
|
printf("\n");
|
|
for (size_t i = 0; i < 2; i++) {
|
|
printf("arr2[1][%zu] Address: %p Value: %d\n", i, &arr2[1][i], *(arr2[1] + i));
|
|
}
|
|
printf("\n");
|
|
for (size_t i = 0; i < 3; i++) {
|
|
printf("arr2[2][%zu] Address: %p Value: %d\n", i, &arr2[2][i], arr2[2][i]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
}
|
|
|
|
|
|
// test safeCompare function
|
|
{
|
|
// test with char parameters
|
|
char a[] = "wurst";
|
|
char b[] = "wurst";
|
|
|
|
if(safeCompare(a, b, sizeof(a), sizeof(b))) {
|
|
printf("%s ungleich %s\n", a, b);
|
|
} else {
|
|
printf("%s gleich %s\n", a, b);
|
|
}
|
|
|
|
// test with int parameters
|
|
int bla[] = {0,1,2,3,4};
|
|
int bli[] = {0,1,2,3,4};
|
|
|
|
if(safeCompare(bla, bli, sizeof(bla), sizeof(bli))) {
|
|
printf("%s ungleich %s\n", "bla", "bli");
|
|
} else {
|
|
printf("%s gleich %s\n", "bla", "bli");
|
|
}
|
|
|
|
// test with unsigned char parameters
|
|
unsigned char blar[] = {0x00, 0x01, 0x02, 0x03, 0x04};
|
|
unsigned char blir[] = {0x00, 0x01, 0x02, 0x03, 0x04};
|
|
|
|
if(safeCompare(blar, blir, sizeof(blar), sizeof(blir))) {
|
|
printf("%s ungleich %s\n", "blar", "blir");
|
|
} else {
|
|
printf("%s gleich %s\n", "blar", "blir");
|
|
}
|
|
|
|
// test with unsigned char
|
|
unsigned char blab = 0x00;
|
|
unsigned char blib = 0x01;
|
|
|
|
if(safeCompare(&blab, &blib, sizeof(blab), sizeof(blib))) {
|
|
printf("%s ungleich %s\n", "blar", "blir");
|
|
} else {
|
|
printf("%s gleich %s\n", "blar", "blir");
|
|
}
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|