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[3], msg_str[MSG_LEN+1];
    int day, i ,j, num_remind = 0;
    
    for(;;){
        if(num_remind == MAX_REMIND){
            printf("--No space left--
");
            break;
        }
        
        printf("Enter day and reminder:");
        scanf("%2d",&day);
        if (day == 0) break;
        sprintf(day_str, "%2d",day);
        read_line(msg_str,MSG_LEN);         //读取字符串
        
        for(i=0;i<num_remind;i++)           //将日期靠前的提醒放在前面
            if(strcmp(day_str,reminders[i]) < 0)    break;
        for(j=num_remind;j>i;j--)
            reminders[j]=reminders[j-1];
        
        reminders[i] = malloc(2 + strlen(msg_str) + 1 );
        if(reminders[i] == NULL)    printf("--No space left--
");
        
        strcpy(reminders[i],day_str);
        strcat(reminders[i],msg_str);
        
        num_remind++;
        
    }
    printf("
 Day Remind
");
    for(i=0;i<num_remind;i++)
        printf("%s
",reminders[i]);
    
    return 0;
}

int read_line(char str[], int n){
    int ch, i=0;
    while ( (ch=getchar()) !='
')
        if(i<n)
            str[i++]=ch;
    str[i]='
';
    return i;
}