yes.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>

#define UNUSED(x) (void)(x)

static volatile int KeepRunning = 1;


void InterceptionSignalHandler(int dummy) {
  UNUSED(dummy);
  if (KeepRunning) {
    KeepRunning = !KeepRunning;
  }
}

int main(int argc, char* argv[]) {
  char* outChar;
  if (argc > 1) {
    for (int i = 1; i < argc; ++i) {
      if (i == 1) {
        outChar = (char*) malloc(strlen(argv[i]));
        strcpy(outChar, argv[i]);
        continue;
      }
      char* newChar = (char*) malloc(strlen(outChar) + 1 + strlen(argv[i]));
      strcpy(newChar, outChar);
      strcat(newChar, " ");
      strcat(newChar, argv[i]);
      free(outChar);
      outChar = newChar;
    }
  } else {
    outChar = (char*) malloc(1);
    strcpy(outChar, "y");
  }
  signal(SIGINT, InterceptionSignalHandler);
  while (KeepRunning) {
    printf("%s\n", outChar);
  }
  free(outChar);
  return 0;
}