Computer Programming 1 Lab

2020-12-03

張麒竑

Outline

  • Input/Output
  • Struct
  • Exercise 9
  • Assign9 Hint

Input/Output

Input/Output

printf

  • Specifier
    /* Signed decimal integer */
printf("%d\n", 455);    // 455
printf("%d\n", +455);   // 455
printf("%d\n", -455);   // -455
printf("%ld\n", 2000000000L);   // 2000000000
/* Unsigned octol integer */
printf("%o\n", 455);    // 707
/* Unsigned decimal integer */
printf("%u\n", 455);    // 455
printf("%u\n", -455);   // 4294966841
/* Unsigned hexadecimal integer */
printf("%x\n", 455);    // 1c7

Input/Output

printf

  • Output format - integer
    printf("%8d***\n", 123);
printf("%8d***\n", -123);
printf("%-8d***\n", 123);
printf("%-8d***\n", -123);
printf("%8d***\n", 123456789);
printf("%8d***\n", -123456789);
printf("\n");
printf("%d\n%d\n", 64, 64);
printf("%04d\n%04d\n", 64, 64);

Input/Output

  • Output format - integer (cont.)
         123***
    -123***
123     ***
-123    ***
123456789***
-123456789***

64
64
0064
0064

Input/Output

  • Output format - float
    printf("%f\n", 3.14159);
printf("%10f\n", 3.14159);
printf("%.2f\n", 3.14159);
printf("%10.2f\n", 3.14159);
    Output:
    3.141590
  3.141590
3.14
      3.14

Input/Output

sprintf

Write formatted data to string

int sprintf( char* str, const char* format, ...)
  • str: string being processed
  • format: string format you want
  • Retuen value:
    • On success, the total number of characters written is returned.
    • On failure, a negative number is returned.

Input/Output

#include <stdio.h>
int main(){
    char buf[50];
    int n;
    int a = 5;
    int b = 3;

    n = sprintf(buf, "%d + %d = %d", a, b, a+b);
    printf("%s\n", buf);
    printf("%d\n", n);
    return 0;
}

Output:

5 + 3 = 8
9

Input/Output

scanf

Precise input formatting can be accomplished with scanf

scanf(format_control_string, other_arguments);
  • format_control_string describes the formats of the input.
  • ither_arguments are pointers to variables in which the input will be stored.

Input/Output

// year, month, and day are "int"
scanf("%d-%d-%d", &year, &month, &day);

// year, month, and day are "int"
scanf("%d%*c%d%*c%d", &year, &month, &day);

// character is a "char"
scanf("%c\n", &c);

// string is a "char" array
scanf("%s", string);

Input/Output

gets

char *gets(char* str)
  • Reads a line from stdin and stores it into the string pointed to by str.
  • It stops when either the newline character is read or when the end-of-file is reached, whichever comes first.

Input/Output

#include <stdio.h>

int main () {
   char str[50];

   printf("Enter a string : ");
   gets(str);

   printf("You entered: %s", str);

   return(0);
}

Output:

Enter a string : This is a cat.
You entered: This is a cat.

Struct

Struct

  • Structures are collections of related variables under one name.
  • Structures may contain variables of many different data types.
    • Arrays contain only elements of the same data types.
struct student{
    char name[20];
    char gender;
    int age;
    struct student* next;
};

struct student stud;
strcpy(stud.name, "Chi-Hung");
stud.gender = 'M';
stud.age = 22;

printf("Name: %s\n", stud.name);
printf("Gender: %c\n", stud.gender);
printf("Age: %d\n", stud.age);

Output:

Name: Chi-Hung
Gender: M
Age: 22

Typedef

  • Define the structure first, then use typedef.
    struct student{
    char name[20];
    char gender;
    int age;
    struct student* next;
};
typedef struct student Student;
  • Use typedef when defining the structure.
    typedef struct student{
    char name[20];
    char gender;
    int age;
    struct student* next;
} Student;

Exercise 9

計算文章出現的每個單字所出現的次數

  • 所有標點符號及數字都不能出現
  • 輸入不只一行
  • 所有的單字都要用小寫來計算（例：The和the視為同一個單字）
  • 輸出的單字順序要用字典排序

Get exercise 9 folder by command line

oj get_assign ex9

Submit your exercise 9 script by command line

oj submit ex9 <your_script_file>
  • Input
    I have a pen. I have an apple.
Uhh!! Apple-pen.

I have a pen. I have a pineapple.
Uhh!! Pineapple-pen.

Apple-pen. Pineapple-pen.
Uhh!! Pen pineapple apple pen.
  • Output
    a 3
an 1
apple 4
have 4
i 4
pen 8
pineapple 4
uhh 3

Assign9 Hint

因為打英文太累，而且麒竑的英文頗爛，所以我打中文

Assign9 Hint

  • 輸入格式
    • 車站
      • 站數
      • 停靠站及停靠順序（由北往南或由南往北，不會有亂跳的狀況）
    • 訂位
      RESERVE NAME, FROM, TO, #tickets, SEAT(s)
    • 取消
      CANCEL NAME, FROM, TO, SEAT
    • 查詢
      CANCEL NAME, SEAT

Assign9 Hint

  • 輸出格式
    • 訂位
      RESERVE SUCCESSED!! -> NAME SEAT (FROM - TO)
RESERVE FAILED.... (station information has something wrong)
RESERVE FAILED.... (too many seats)
RESERVE FAILED.... (repest seats)
    • 取消
      CANCELLATION SUCCESSED!! SEAT (FROM - TO)
CANCELLATION FAILED.... (cannot find the stations information)
CANCELLATION FAILED.... (cannot find the seat information)
    • 查詢
      CHECK NAME SEAT -> (FROM - TO)
CHECK FAILED.... (cannot find the reservation data)

Assign9 Hint

  • 訂位
    1. 一次最多訂4張票
    2. 全部座位都成功才算那一筆的訂位是成功的！否則該筆訂位就是失敗
    3. 有關車站的訂位失敗
      • 起訖站有出現列車不會停靠的車站
      • 起訖站與列車行進方向相反
    4. 有關車票張數的訂位失敗
      • 訂票超過4張
    5. 有關座位的訂位失敗
      • 訂票的位子已經有被預訂走了
      • 同一筆訂位出現重複的位子
    6. 若有多個訂位失敗原因，印出原因的優先順序為「車站->車票張數->座位」

Assign9 Hint

  • 取消
    1. 當那個"人"在輸入的"指定區間"內在"指定座位"都有訂位，則可成功取消該訂位（三個條件缺一不可）
    2. 取消不是取消那個座位訂位時的區間，而去取消現在"這個取消指令"所指定的區間的訂位
    3. 只需要看現在的指定區間，不需要看區間前後的訂位狀況（所以有可能會出現一段訂位但中間被取消的狀況）
    4. 只需要看現在的指定座位，不需要看這個座位在訂位時同時訂的其他座位

Assign9 Hint

  • 查詢
    1. 需印出那個人在指定座位的起訖站
    2. 只要那個人在該指定座位沒有任何訂位，則顯示查詢錯誤
    3. 如果那個人在指定座位有多段區間（例：新竹->台中、台南->高雄），則需要將所有區間都印出來，並用空格分隔每個區間，印出順序是依照列車的行進順序（如：列車是由北往南行駛，則「新竹->台中」先印出，「台南->高雄」後印出）
    4. 如果有兩次的訂位在同一個座位，且區間為相連的（例：台北->新竹、新竹->台中），則在查詢時須將兩個區間相連一起顯示（如：台北->台中）

Assign9 Hint

  • 貼心(??)小提示
    1. 測資中有許多的分隔行，記得也要將這些分隔行讀進來
    2. 每個,後面都有一個空格，在做字串分割的時候要注意！！
    3. 建議讀取測資用gets來讀取，再來做字串分割
    4. 有關輸出格式，如果上面的投影片不清楚，可以去範例輸出看，我有把所有可能的輸出狀況都列出來了
    5. 麒竑很友善，拜託不要來揍我OAO

Any Question?