工作日发现者奇怪的行为

Question

这是我整理的一周查找程序。一切正常，但一方面我无法弄清楚。它将采用的唯一日期格式是 dd/mm/yyyy.

我不明白的是：有一个函数可以检查输入的日期是否有效，方法是确保输入的日期在月份范围内，并且月份的值小于 12。每次输入八月或九月的日期（8 月和 9 月）时，它都无法读取。经过一些调试后，似乎在输入这些值时（输入示例：01/08/2014），sscanf("%i%i%i", day, month, year) returns 2 而不是 3，和所以它认为该条目无效。我不明白为什么它适用于任何其他日期，但不适用于八月或九月。

程序：

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

#define SIZE 15


typedef char* string;
string weekDay[7] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
int month_days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};


//Function prototypes
void getInput(string prompt, int* day, int* month, int* year);
bool dateChecking(int *day, int *month, int *year);
bool isLeapYear(int year);
int getCenturyValue(int year);
int getYearValue(int year);
int getMonthValue(int month, int year);



//Read in the date to be analyzed.
void getInput(string prompt, int* day, int* month, int* year)
{
    int success;
    char buffer[SIZE];

    do
    {
        printf("%s", prompt);
        fgets(buffer, sizeof(buffer), stdin);
        success = sscanf(buffer, "%i/%i/%i", day, month, year);

        if ((success < 3) || !(dateChecking(day,month,year)))
            printf("You made an invalid entry. Please try again.\n");

    }while ((success <3) || !(dateChecking(day,month,year)));
}


//Check if the day and months are withing allowable ranges.
bool dateChecking(int *day, int *month, int *year)
{
    if (isLeapYear(*year))
        month_days[1] =  29;

    if (*month < 13)
        return (*day < month_days[*month-1]);

    else return false;

}



//Returns true if the year is a leap year.
bool  isLeapYear(int year){

    return ((year%400 == 0) || ((year%4 == 0)&&(year%100 !=0)));
}



//Extract the first two digits of the year, and process it
//according to the assignment spec.
int getCenturyValue(int year) {

    int value = year/100;
    return 2*(3 - (value % 4));
}


//Extract the last two digits of the year, and process it
//according to the assignment spec.
int getYearValue(int year){

    int value = year - ((year/100)*100);

    return value + (value/4);
}


//switch statement to relate each month to its value
int getMonthValue(int month, int year){

    int value = 0;

    switch (month) {
        case 1: value = isLeapYear(year)? 0 : 6; break;
        case 2: value = isLeapYear(year)? 3 : 2; break;
        case 3: value = 3; break;
        case 4: value = 6; break;
        case 5: value = 1; break;
        case 6: value = 4; break;
        case 7: value = 6; break;
        case 8: value = 2; break;
        case 9: value = 5; break;
        case 10: value = 0; break;
        case 11: value = 3; break;
        case 12: value = 5; break;
    }
    return value;
}



int main()
{

    int day, month, year, sum;


    getInput("Enter a date in the following format: dd/mm/yyyy: ", &day, &month, &year);
    sum = day + getMonthValue(month,year) + getYearValue(year) + getCenturyValue(year);


    printf("The date specified is a: %s", weekDay[sum % 7]);


    printf("\n\n\n");
    return 0;
}

Answer 1

您需要使用 sscanf 将 %i 更改为 %d。使用 %i 将前缀为 0 的数字解释为八进制。

工作日发现者奇怪的行为

week day finder strange behavior

c

scanf