malloc动态分配字符串数组“ 一个月内的提醒”

 //输出一个月提醒

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

 #define MAX_REMIND 50            //提醒的数量
 #define MSG_LEN 60              //提醒的长度
 int main(void){
     int read_line(char str[], int n);
     char *reminders[MAX_REMIND];
     char day_str[], msg_str[MSG_LEN+];
     int day, i ,j, num_remind = ;

     for(;;){
         if(num_remind == MAX_REMIND){
             printf("--No space left--\n");
             break;
         }

         printf("Enter day and reminder:");
         scanf("%2d",&day);
         if (day == ) break;
         sprintf(day_str, "%2d",day);
         read_line(msg_str,MSG_LEN);         //读取字符串

         for(i=;i<num_remind;i++)           //将日期靠前的提醒放在前面
             if(strcmp(day_str,reminders[i]) < )    break;
         for(j=num_remind;j>i;j--)
             reminders[j]=reminders[j-];

         reminders[i] = malloc( + strlen(msg_str) +  );
         if(reminders[i] == NULL)    printf("--No space left--\n");

         strcpy(reminders[i],day_str);
         strcat(reminders[i],msg_str);

         num_remind++;

     }
     printf("\n Day Remind\n");
     for(i=;i<num_remind;i++)
         printf("%s\n",reminders[i]);

     return ;
 }

 int read_line(char str[], int n){
     int ch, i=;
     while ( (ch=getchar()) !='\n')
         if(i<n)
             str[i++]=ch;
     str[i]='\n';
     return i;
 }