From Gossip@caterpillar

C Gossip: ぃ﹚ま计Variable-length argument

﹚竡ㄧΑΤи礚猭ㄆ眔璶肚患把计计硂娩ざ残ぃ﹚ま计Variable-length argumentㄏノ璶ㄏノぃ﹚ま计眤ゲ斗stdarg.h繷郎
#include <stdarg.h>

ぃ﹚ま计ㄏノ碭醚ㄓミぃ﹚ま计
  • va_list
疭篈typeva_start va_arg籔va_endエ 栋macro讽把计ㄏノ
  • va_start
币﹍ぃ﹚ま计エ栋
  • va_arg
弄ぃ﹚ま计エ栋
  • va_end
沧ゎぃ﹚ま计エ栋

ぃ﹚ま计眤ㄧΑ﹚竡ㄏノ ... ボ盢ㄏノぃ﹚ま计τぇ玡ゲ斗盢肚患碭ぃ﹚ま计ㄒ
void foo(int, ...);

ㄏノva_argエ栋ま计ず甧眤ゲ斗﹚盢贺戈篈ㄒ
va_arg(num_list, double);

硂祘Αボ絛ㄏノぃ﹚ま计
#include <stdio.h>
#include <stdarg.h>

void foo(int, ...);

int main(void) {
double x = 1.1, y = 2.1, z = 3.9;
double a = 0.1, b = 0.2, c = 0.3;

puts("把计");
foo(3, x, y, z);

puts("せ把计");
foo(6, x, y, z, a, b, c);

return 0;
}

void foo(int i, ...) {
double tmp;
va_list num_list;

va_start(num_list, i);

int j;
for(j = 0; j < i; j++) {
printf("%.1f\n", va_arg(num_list, double));
}

va_end(num_list);
}

磅︽挡狦
把计
1.1
2.1
3.9
せ把计
1.1
2.1
3.9
0.1
0.2
0.3