#include<stdio.h>
char * const mon1(int i)
{
  char *m;
  if(i<12){
    if(i == 1){
      m="January";
    }else if(i == 2){
      m="February";
    }else if(i == 3){
      m="March";
    }else if(i == 4){
      m="April";
    }else if(i == 5){
      m="May";
    }else if(i == 6){
      m="June";
    }else if(i == 7){
      m="July";
    }else if(i == 8){
      m="August";
    }else if(i == 9){
      m="September";
    }else if(i == 10){
      m="October";
    }else if(i == 11){
      m="November";
    }else if(i == 12){
      m="December";
    }
  }else{
    m = NULL;
  }
  return m;
}

void mon2(int i, char **m)
{
  if(i<12){
    if(i == 1){
      *m="January";
    }else if(i == 2){
      *m="February";
    }else if(i == 3){
      *m="March";
    }else if(i == 4){
      *m="April";
    }else if(i == 5){
      *m="May";
    }else if(i == 6){
      *m="June";
    }else if(i == 7){
      *m="July";
    }else if(i == 8){
      *m="August";
    }else if(i == 9){
      *m="September";
    }else if(i == 10){
      *m="October";
    }else if(i == 11){
      *m="November";
    }else if(i == 12){
      *m="December";
    }
  }else{
    *m = NULL;
  }
}

int main(void)
{
  int i;
  char *c;

  printf("数字を入力:");
  scanf("%d",&i);
  c = mon1(i);
  if (c != NULL)
    printf("%s\n",c);
  mon2(i, &c);
  if (c != NULL)
    printf("%s\n",c);

  return 0;
}
/* end */

数字を入力: