Modify variable or struct inside a C function - c

I wanted to make a game of life in C to learn C, but it doesn't work. I just noticed that my code doesn't work when I try to modify a variable created inside a function, even if I try to modify it inside the same function.
When I pass val = 1 in comment, and color in comment, the code works
so val = 0 doesn't cause problem, neither color = {0,0,0,0} because it doesn't modify the variable.
How can I do to correct it ?
void next_grid(int nbc, int nbr,Cell tab[][120],Cell newtab[][120]){
for (int y = 0; y<120; y++){
for(int x = 0; x<120; x++){
int nb_neighbors = count_neighbors(tab,120,120,y,x);
int val = 0;
Color color = {0,0,0,0};
// When a cell is dead
if (tab[y][x].val == 0)
{
if (nb_neighbors == 3)
{
val = 1;
color = (Color) {230,160,0,255};
}
else{
val = 0;
color = (Color) {0,0,0,255};
}
}
{
if (nb_neighbors == 2 || nb_neighbors == 3)
{
val = 1;
color = (Color) {230,160,0,255};
}
else
{
val = 0;
color = (Color) {0,0,0,255};
}
}
newtab[y][x] = (Cell) {val,x,y,color};
}
}
// swap array
for (int y = 0; y<120; y++){
for(int x = 0; x<120; x++){
tab[y][x] = (Cell) newtab[y][x];
}
}
}

Related

pass by value not supported XDP

I am creating a function to loop through some loops and try to match a set. It is supposed to work fine, but unfortunately, it is not. I get a "pass by value not supported" error. How can I fix this?
int matchSet(Program p, int match[], int action)
{
int matchState = 0;
int match[4] = {3,4,5,6}; //set as example
int p.set[10] = {2,1,3,4,5,6,9,10,11,12}; //set as example (normal p.set)
for (int i = 0; i < 10; i++)
{
if (matchState != 2)
{
if (p.set[i] == match[0] && p.set[i + 1] == match[1])
{
matchState = 0;
for (int j = 0; j <= 4; j++)
{
bpf_printk("test");
if (matchState == 0)
{
bpf_printk("test3");
if (p.set[i] != match[j])
{
bpf_printk("test4");
matchState = 1;
break;
}
}
}
if (matchState == 0)
{
bpf_printk("test6");
matchState = 2;
}
}
}
}
if(matchState == 2) {
return action;
}
}
I call the function by:
Program p;
.....
int set[10] = {2,1,3,4,5,6,9,10,11,12};
p.set = set;
int match[4] = {3,4,5,6};
matchSet(p, match, 1);
Error:
error: pass by value not supported 0x1aca7c8: i64 = GlobalAddress<i32 (%struct.Program*, i8*, i32)* #matchSet> 0
You need to change your function to take a pointer to a Program like so:
int matchSet(Program *p, int match[], int action){
...
And then also change your callsite:
Program p;
matchSet(&p, match, 1);

C Program numbers not sorting array correctly

I have an array of structs for products that I am trying to sort by name, type, price, and quantity. Name and type work, but price and quantity aren't working.
My code is:
else if (sort == sortByPrice)
{
for (int i = 0; i < numProducts; i++)
{
int smallPosition = i;
for (int x = i + 1; x < numProducts; x++)
{
if (list[i].price > list[x].price)
{
smallPosition = x;
}
}
temp = list[i];
list[i] = list[smallPosition];
list[smallPosition] = temp;
}
}
else if (sort == sortByQty)
{
for (int i = 0; i < numProducts; i++)
{
int smallPosition = i;
for (int x = i + 1; x < numProducts; x++)
{
if (list[i].qty > list[x].qty)
{
smallPosition = x;
}
}
temp = list[i];
list[i] = list[smallPosition];
list[smallPosition] = temp;
}
}
Can anyone tell me why it doesn't work/how to fix it?
Following up on Lee Daniel Crocker's comment, you should dynamically compare with the value at smallPosition instead of i so that it will always point to the smallest remaining item:
int smallPosition = i;
for (int x = i + 1; x < numProducts; x++)
{
if (list[smallPosition].price > list[x].price)
{
smallPosition = x;
}
}
You should move the swap code inside the if statement:
for (int i = 0; i < numProducts; i++)
{
for (int x = i + 1; x < numProducts; x++)
{
if (list[i].price > list[x].price)
{
temp = list[i];
list[i] = list[X];
list[X] = temp;
}
}
}
Just use bubble sort.
In the bubble sort you swap the values of the current value is bigger than the next one, if you do this action until you get to the end of the array then the array will be sorted.

Filling values in 1D array

Code Fragment
if (val==1)
paperR[LIMIT]={100,50,20,10,5,2,1};
else if (val==2)
paperR[LIMIT]={200,100,50,20,10,5,1};
PROBLEM ?
it's like doing
int ask;
LATER IN CODE
ask=1;
How to do it with array ?
You can't assign to an array, you can only provide a list of values if you're initializing the array at the point where it's being declared.
If you want to fill in an array, you can use memcpy from another array that contains the values you want to use. So you can declare:
const int arr100[] = {100,50,20,10,5,2,1};
const int arr200[] = {200,100,50,20,10,5,1};
int paperR[LIMIT];
if (val == 1) {
memcpy(paperR, arr100, sizeof arr100);
} else if (val == 2) {
memcpy(paperR, arr200, sizeof arr200);
}
You may do it by one element after other:
if (val==1)
{
paperR[0] = 100;
paperR[1] = 50;
paperR[2] = 20;
paperR[3] = 10;
paperR[4] = 5;
paperR[5] = 2;
paperR[6] = 1;
}
else if (val==2)
{
paperR[0] = 200;
paperR[1] = 100;
paperR[2] = 50;
paperR[3] = 20;
paperR[4] = 10;
paperR[5] = 5;
paperR[6] = 1;
}

Boolean fuction to all the elements in an array processing 3.0

I'm trying to make a program which shows some circles, and when the user puts all the circles in one place, the background changes. The problem I have is that when one circle is moved to that place the background changes, but I need that to happened once all the elements of the array had changed position..
DragMe[] drags = new DragMe[15];
PGraphics topLayer;
PGraphics toperLayer;
color backgr;
void setup() {
size(500, 500);
for (int i = 0; i < drags.length; i++) {
drags[i] = new DragMe();
}
topLayer = createGraphics(width, height, g.getClass().getName());
}
void draw() {
background(backgr);
{
topLayer.beginDraw();
topLayer.noFill();
topLayer.stroke(0 );
if (mousePressed ==true) {
topLayer.line( pmouseX, pmouseY, mouseX, mouseY );
topLayer.endDraw();
}
image( topLayer, 0, 0 );
}
for (int i = 0; i < drags.length; i++) {
drags[i].display();
drags[i].update();
}
for (int i = 0; i < drags.length; i++) {
drags[i].fondo();
}
{
ellipse(width/2.5, height/2.5, 110, 110);
fill(255);
}
}
void mousePressed() {
for (int i = 0; i < drags.length; i++) {
if (!drags[i].isOver())
drags[i].dontMove = true;
drags[i].offset_x = mouseX - drags[i].pos_x;
drags[i].offset_y = mouseY - drags[i].pos_y;
}
}
void mouseReleased() {
for (int i = 0; i < drags.length; i++) {
drags[i].locked = false;
drags[i].dontMove = false;
}
}
class DragMe {
float pos_x, pos_y, SIZE = 25;
float prev_x, prev_y;
boolean locked;
boolean dontMove;
boolean all;
color c = color (255);
float offset_x, offset_y;
DragMe() {
pos_x = random(width-SIZE);
pos_y = random(height-SIZE);
}
void update() {
if (isOver() && !locked && !dontMove || locked && !dontMove )
c = color (255);
else
c = color (255);
if (isClicked()) {
locked = true;
}
if (isIn()) {
locked = false;
all = true;
}
if (locked && !dontMove) {
pos_x = mouseX - offset_x;
pos_y = mouseY - offset_y;
}
}
void display() {
fill(c);
ellipse(pos_x, pos_y, SIZE, SIZE);
ellipseMode(CORNER);
noStroke();
}
boolean isOver() {
float right_x = pos_x + SIZE;
float bottom_y = pos_y + SIZE;
return mouseX >= pos_x && mouseX <= right_x &&
mouseY >= pos_y && mouseY <= bottom_y;
}
boolean isClicked() {
return isOver() && mousePressed && !dontMove;
}
boolean isIn() {
float right_x = pos_x + SIZE;
float bottom_y = pos_y + SIZE;
return right_x >= width/2.5 + SIZE && right_x <= width/2.5 + 100 &&
bottom_y >= height/2.5 + SIZE && bottom_y <= height/2.5 + 100;
}
void fondo() {
if (all == true)
backgr= 255;
}
}
You have 15 instances of DragMe.
Each of those instances contains a variable named all.
When one instance's all is true, you set the background to white.
Specifically, this function:
void fondo() {
if (all == true)
backgr= 255;
}
Which you call from draw():
for (int i = 0; i < drags.length; i++) {
drags[i].fondo();
}
Instead, you need to check every instance's all variable, and only change the background if they are all true (in other words, if none of them are false):
boolean allIn = true;
for (int i = 0; i < drags.length; i++) {
if (!drags[i].all) {
allIn = false;
}
}
if (allIn) {
backgr= 255;
}
For future questions, please try to make sure your code is formatted. It might also be a good idea to use better variable names- naming a variable all is a bit hard to talk about. Maybe something like isInsideWhiteCircle would be better.

MiniMax TicTacToe doesn't work (c)

I have implemented a TicTacToe algorythm with MiniMax, but the problem is that the computer always just places an 'x' on the next possible spot instead of evaluating the game. Does anybody know why ? (The problem can only be in the MiniMax function, or the nextMove function.)
Thanks a lot in advance !!
Here's the code :
int MiniMax(struct Game g, enum Symbol pl){
int score;
if (pl==CROSS)
{
score = -98765;
}
else score = 98765;
int temp_cross =0;
int temp_circle =0;
//base case
if (game_over(g) == CROSS)
return 10;
else if (game_over(g) == CIRCLE)
return -10;
else if (game_over(g) == FULL)
return 0;
int x,y;
for (y=0; y<SIZE_Y_AXIS; y++)
{
for (x=0; x<SIZE_X_AXIS; x++)
{
if (g.board.fields[x][y] == NONE)
{
if (pl == CROSS)
g.board.fields[x][y] = CROSS;
else g.board.fields[x][y] = CIRCLE;
if (pl == CROSS)
temp_cross= MiniMax(g, CIRCLE);
else temp_circle = MiniMax(g, CROSS);
g.board.fields[x][y] = NONE;
if ((pl == CROSS) && (temp_cross > score))
score = temp_cross;
else if ((pl == CIRCLE) && (temp_circle < score))
score = temp_circle;
}
}
}
return score;
};
int nextMove(struct Game g, enum Symbol player){
int score_cross = -865435;
int score_cross_temp = 0;
int cross_position = 1;
int score_circle = 876545;
int score_circle_temp = 0;
int circle_position = 1;
int x,y;
for (y=0; y<SIZE_Y_AXIS; y++)
{
for (x=0; x<SIZE_X_AXIS; x++)
{
if (g.board.fields[x][y] == NONE)
{
if (player == CROSS)
{
score_cross_temp = MiniMax(g, CROSS);
printf("%d ",MiniMax(g, CROSS));
if (score_cross_temp > score_cross)
{
score_cross = score_cross_temp;
cross_position = (y)*3 + x+1;
}
}
else if (player == CIRCLE)
{
score_circle_temp = MiniMax(g, CIRCLE);
if (score_cross_temp < score_circle)
{
score_circle = score_circle_temp;
circle_position = (y)*3 + x+1;
}
}
}
}
}
if (player == CROSS)
{
//printf("%d",cross_position);
return cross_position;
}
else
{
//printf("%d",circle_position);
return circle_position;
}
};
I believe there is a bug in your code. You initialize score as 10, and the temp variables as arbitrarily high and low numbers. This is backwards. TempCircle and TempCross are being overwritten anyway my the calls to minimax. It is the score variable that must be set like that. replace
int score = 10;
int temp_cross = -9876543;
int temp_circle = 9876543;
with
int score;
if(pl==cross){
score = 9876543
}
else{
score = -9876543
}
int temp_cross;
int temp_circle;
There also seems to be another bug in your nextMove function. I assume that its purpose is to iterate over all possible moves, find the one with the highest minimax value, and return that move (correct me if I'm wrong). That is not what the function does. It iterates over all the moves, but does't make any of them. x and y are never even used, except to update the move. You are essentially calling the same minimax several times. Instead, I would either get rid of the function completely, as there is a way to do this inside the minimax function, or fix this function. To fix the function, I would change it to this:
int nextMove(struct Game g, enum Symbol player){
int score_cross = -865435;
int score_cross_temp = 0;
int cross_position = 1;
int score_circle = 876545;
int score_circle_temp = 0;
int circle_position = 1;
int x,y;
for (y=0; y<SIZE_Y_AXIS; y++)
{
for (x=0; x<SIZE_X_AXIS; x++)
{
if (g.board.fields[x][y] == NONE)
{
if (player == CROSS)
{
g.board.fields[x][y] = CROSS;
score_cross_temp = MiniMax(g, CIRCLE);
printf("%d ",MiniMax(g, CROSS));
g.board.fields[x][y] = NONE;
if (score_cross_temp > score_cross)
{
score_cross = score_cross_temp;
cross_position = (y)*3 + x+1;
}
}
else if (player == CIRCLE)
{
g.board.fields[x][y] = CIRCLE;
score_circle_temp = MiniMax(g, CROSS);
g.board.fields[x][y] = NONE;
if (score_cross_temp < score_circle)
{
score_circle = score_circle_temp;
circle_position = (y)*3 + x+1;
}
}
}
}
}
if (player == CROSS)
{
//printf("%d",cross_position);
return cross_position;
}
else
{
//printf("%d",circle_position);
return circle_position;
}
};
Or you can edit minimax to keep track of which call to the function it is. If it is the first recursive call (the root) , keep track of the move itself as well as its value. Then return the move.

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