Category : Files from Magazines
Archive   : DDJ0892.ZIP
Filename : NCEG.ASC

_NUMERIC EXTENSIONS TO C_
by Robert Jervis

Example 1:

(a)

void f3(int n, float *restrict a, float *b, float *c) {
int i;
for (i = 0; i < n; i++)
a[i] = b[i] + c[i];
}



(b)

float x[100];
float *c;

void f5(int n, float *restrict a, float *restrict b) {
int i;
for (i = 0; i < n; i++)
a[i] = b[i] + c[i];
}
void g5(void) {
float d[100], e[100];
c = x;

f5(100, d, e); /* Behavior defined. */
f5( 50, d, d+50); /* Behavior defined. */
f5( 99, d+1, d); /* Behavior undefined. */
c = d;
f5(100, d, e); /* Behavior undefined. */
f5(100, e, d); /* Behavior defined. */
}



Example 2:

(a)
shape [10][10] Sa;

double:Sa a, b, c;

f() {
double n;
int i;

a = b + c;
n = [4][i]b + 2.0;
where (b < 5){
a++;
c = b;
}
}

(b)

void f(void) {
iterator I = 100;
float a[100], b[100];

a[I] = b[I] + 1;
}


(c)

void f(void) {
int I;
float a[100], b[100];

for (I = 0; I < 100; I++)
a[I] = b[I] + 1;
}

Example 3:


float x, y, z;
long double u, v;

u = (x + y) * (z + v);

Example 4:

double complex x;

x = 3 + 5i;


Example 5:

(a)

void f(int m, float *a) {
... a[i * m + j] ...
}


(b)

void f(int m, float a[m][m]) {
... a[i][j] ...
}




(c)


void f(int n) {
float a[n];
/* ... */
}



Example 6:

(a)


div_t answer = { .quot = 1, .rem = 0 };


(b)

enum etag { Mem1, Mem2, /* ... */ };

const char *nm[] = { [Mem2] = "Mem2", [Mem1] = "Mem1",
/* ... */ };


(c)

int a[MAX] = {
1, 3, 5, 7, 9, [MAX-5] = 8, 6, 4, 2, 0
};


(d)

struct s { int a[3], b; };
struct s w[] = { [0].a = { 1 }, [1].a[0] = 2 };
struct s z[] = { { 1 }, 2 };


(e)

union utag { /* ... */ } u = { .any_member = 42 };


(f)

struct point { int x, y };
void drawCircle(struct point center, int radius);

struct point p;

p.x = 11; p.y = 12;
drawCircle(p, 15);

drawCircle((struct point){ 11, 12 }, 15);

Example 7:

int:32 x;
int {1 .. 100} y;