c：帶支柱和陣列的字符串輸入

Question

我正在編寫一個程序，當用戶輸入月份和日期編號時，將輸出月份和年份日期。預期的輸入和輸出如下。

Enter month and day number? december 30 
December (DEC) 31 means 364 days YTD. 

我的程序沒有編譯，我使用的是Microsoft Visual Studio。使用與預期輸入相同的輸入我試圖運行程序;但是，輸入月份和日期編號後，程序崩潰。從編譯器

警告：

'scanf_s' : format string '%s' requires an argument of type 'unsigned int', but variadic argument 2 has type 'int *'  

'scanf_s' : not enough arguments passed for format string 

當我使用調試器，我輸入的月份和日期後，然後進行單步執行代碼程序給出了這些消息。它似乎沒有足夠的內存來繼續？如果這是問題，解決問題的最合理的方法是什麼？

Exception thrown at 0x0FCA0BA9 (ucrtbased.dll) in lab14program345words.exe: 0xC0000005: Access violation writing location 0x003C0000. 

下面是我的代碼：

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

int finddata(int month, int days); 

struct month 
{ 
    char name[10]; 
    char abbrev[4]; 
    int days; 
    int monumb; 
}; 



int main() 
{ 
    struct month months[12] = 
    { 
     { "January", "jan", 31, 1 }, 
     { "February", "feb", 28, 2 }, 
     { "March", "mar", 31, 3 }, 
     { "April", "apr", 30, 4 }, 
     { "May", "may", 31, 5 }, 
     { "June", "jun", 30, 6 }, 
     { "July", "jul", 31, 7 }, 
     { "August", "aug", 31, 8 }, 
     { "September", "sep", 30, 9 }, 
     { "October", "oct", 31, 10 }, 
     { "November", "nov", 30, 11 }, 
     { "December", "dec", 31, 12 } 
    }; 
    struct month userdata; 
    int i = 0; 
    int total; 

    do 
    { 
     printf("Enter month and day number:"); 

     scanf_s("%s %d", userdata.name, &userdata.days); //line 42, where the warnings occur 

     toupper(userdata.name[0]); 

     if (strcmp(userdata.name, months[i].name) == 0) // should compare user's entered month to months in month montths array 
     { 
      puts(months[i].name); 
      puts(months[i].abbrev); 
     } 
     else 
     { 
      i++; 
     } 


     total = finddata(months[i].monumb, userdata.days); // should pass the month number and days the user entered. 
     printf("%d days YTD.\n", total); 

    } while ((userdata.monumb > 0) || (userdata.monumb < 13)); 


    return 0; 
} 



int finddata(int months, int days) 
{ 
    int total = 0; 

    if (months == 1) 
    { 
     total = days; 
    } 
    else if (months == 2) 
    { 
     total = days + 31; 
    } 
    else if (months == 3) 
    { 
     total = 31 + 28 + days; 
    } 
    else if (months == 4) 
    { 
     total = 31 + 28 + 31 + days; 
    } 
    else if (months == 5) 
    { 
     total = 31 + 28 + 31 + 30 + days; 
    } 
    else if (months == 6) 
    { 
     total = 31 + 28 + 31 + 30 + 31 + days; 
    } 
    else if (months == 7) 
    { 
     total = (31 * 3) + 28 + (30 * 2) + days; 
    } 
    else if (months == 8) 
    { 
     total = (31 * 4) + 28 + (30 * 2) + days; 
    } 
    else if (months == 9) 
    { 
     total = (31 * 5) + 28 + (30 * 2) + days; 
    } 
    else if (months == 10) 
    { 
     total = (31 * 5) + 28 + (30 * 3) + days; 
    } 
    else if (months == 11) 
    { 
     total = (31 * 6) + 28 + (30 * 3) + days; 
    } 
    else if (months == 12) 
    { 
     total = (31 * 6) + 28 + (30 * 4) + days; 
    } 
    else 
    { 
     //blank 
    } 



    return total; 
} 

Answer 1

scanf_s("%s %d", userdata.name, &userdata.days); 

如果你閱讀scanf_s，它需要通過另一個參數與%s和%c代表長度。

所以你的情況，你需要做的是 -

scanf_s("%s %d", userdata.name, (rsize_t)sizeof userdata.name, &userdata.days); 

你得到警告，因爲&userdata.days被視爲長度參數，並且類型不匹配。 在%c的情況下，您需要通過1來讀取一個字符。