Thread: Vector os structs not working how it is supposed to...

got to write this little program, that reads some points coordinates and do some stuff with it, can't figure out why it doesn't work for more than two points. here is the code:

Code:

#include <stdio.h>#include <stdlib.h>
#include <math.h>
#define DISTANCE sqrt((u[a].x-u[b].x)*(u[a].x-u[b].x)+(u[a].y-u[b].y)*(u[a].y-u[b].y)+(u[a].z-u[b].z)*(u[a].z-u[b].z))


typedef struct{
	int x, y, z;
} point;


typedef point* dots;


//building the structures


dots build(int* num) {
	int size;
	dots Temp;
	
	do{
		printf("Type number of points: ");
		scanf("%d", &size);
		if(size<=0) puts("Invalid Number.");
	}while (size<=0);
	
	Temp = (dots) malloc (sizeof(dots)*size);
	if (Temp == NULL) exit(1);
	*num = size;
	return Temp;
}


//reading the points


void readpoints(dots u, int size){ //u stands for Universe
	int i;
	
	for(i=0; i<size; i++){
		system("cls");
		printf("Point %d: ",  (i+1));
		printf("\nType x coordinate: ");
		scanf("%d", &u[i].x);
		printf("\nType y coordinate: ");
		scanf("%d", &u[i].y);
		printf("\nType z coordinate: ");
		scanf("%d", &u[i].z);
	}
}


//printing the points out


void printp(dots u, int size){
	int i;
	
	printf("Typed points:\n");
	for(i=0; i<size; i++)
		printf("Point %d: {%d, %d, %d}\n", (i+1), u[i].x, u[i].y, u[i].z);
	system("PAUSE");


}


//one funcion for both requests, based on choice


void distance(int choice, dots u, int size){
	float dis;
	if (!choice) {
		int a, b;
		dis=0;
		printf("Type the two points (1 - %d): ", size);
		scanf("%d %d", &a, &b);
		a--; b--;
		dis = DISTANCE;
		system("cls");
		printf("Distance from %d to %d = %f\n", (a+1), (b+1), dis);
	}
	else {
		int a, b;
		for (a=0; a<size; a++){
			dis=0;
			b=a+1;
			dis = DISTANCE;
			system("cls");
			printf("Distance from %d to %d = %f\n", (a+1), (b+1), dis);
		}
	}
	system("PAUSE");
}


//menu


void menu() {
	int choice, num;
	dots universe;
	printf("First we need some POINTS!\n");
	universe = build(&num);
	readpoints(universe, num);
	do{
		system("cls");
		printf("Type\n");
		printf("1: Retype points.\n");
		printf("2: Print typed points.\n");
		printf("3: Calculate distance between two points.\n");
		printf("4: Calculate distance one by one(1-2, 2-3...)\n");
		printf("5: Exit\nChoice: ");
		scanf("%d", &choice);
		switch (choice){
			case 1: universe = build(&num); readpoints(universe, num); break;
			case 2: printp(universe, num); break;
			case 3:
			case 4: distance((choice-3), universe, num); break;
			case 5: choice = 0; break;
			default: 	printf("Invalid entry");
						system("PAUSE");
						choice = 1;
						break;
		}
	}while(choice);
}


//simple main


int main(){
	menu();
	return 0;
}

Code:

Temp = (dots) malloc (sizeof(dots)*size);

You're allocating memory based on the size of a pointer to a structure, not the size of the structure itself.

oh, that makes much more sense than what i was doing...

i will also redefine the macro, thanks!