Source code
#include <stdio.h>
#include <string.h>
/*
* Program to create instances of the particles structure
*/
/* valid particle types */
enum { NEUTRON, PROTON, ELECTRON };
char *names [] = { "neutron", "proton", "electron" };
/* define a vector as a 3D double */
typedef double vector [3];
/* define a string as a character array */
typedef char string [80];
/* eliminate the need to say struct all over the place */
typedef struct {
vector pos;
double mass;
int type;
string name;
} particle;
/* function declarations */
particle initParticle ( int type );
void printParticle ( particle );
int main ( void )
{
/* create an array of three particle structures */
particle particles [3];
/* call the initParticle to initialize these particles */
particles [NEUTRON] = initParticle ( NEUTRON );
printParticle ( particles [NEUTRON] );
particles [PROTON] = initParticle ( PROTON );
printParticle ( particles [PROTON] );
particles [ELECTRON] = initParticle ( ELECTRON );
printParticle ( particles [ELECTRON] );
return ( 0 );
}
/*
* Return an initialized particle based on the enumerated type of the
* argument
*/
particle initParticle ( int type ) {
/* create a particle structure and set values in it */
particle p;
p.pos[0] = 1.1;
p.pos[1] = 2.2;
p.pos[2] = 3.3;
p.mass = 14.2;
p.type = type;
strcpy ( p.name, names[type] );
/* return the newly initialized structure */
return ( p );
}
/*
* Print out the particle
*/
void printParticle ( particle p ) {
printf ( "%s (type %d): (%.2f, %.2f, %.2f), mass %.1f\n", p.name,
p.type, p.pos[0], p.pos[1], p.pos[2], p.mass );
return;
}
Output:
neutron (type 0): (1.10, 2.20, 3.30), mass 14.2
proton (type 1): (1.10, 2.20, 3.30), mass 14.2
electron (type 2): (1.10, 2.20, 3.30), mass 14.2
