在C ++中使用两个char变量评估布尔值

Question

Apologies, a bit of a beginner here:

I'm working on a practice program to determine cost of a long distance call based on hour of the day and day of the week...and I've gotten to my do-while loop and am attempting to use nested branches to split up weekdays with the weekend.

However, when I compile and run, both the if and else if nested statements are skipped no matter if I put in the Chars corresponding to the booleans I'm attempting to evaluate. I'm struggling to understand what I'm missing here. The instructions clearly state that the days of the week should be stored in two char variables: Mo Tu We Th Fr Sa Su.

do
{
    //have user input day of week of call
    printf("\nOn what day was the call made? (Mo, Tu, We, Th, Fr, Sa, or Su) ");
    scanf("%c%c", &day1, &day2);

    //branch for weekday vs weekend vs invalid input
    if (((day1 == 'M') && (day2 == 'o')) || ((day1 == 'T') && (day2 == 'u')) || ((day1 == 'W') && (day2 == 'e')) || ((day1 == 'T') && (day2 == 'h')) || ((day1 == 'F') && (day2 == 'r')))
    {
        //determine if phone call was made at hi or low rate times
        printf("At what time was your call made? (HH MM - with 08 00 representing 8:00 AM and 18 30 representing 6:30 PM) ");
        scanf("%f %f", &call_time_hour, &call_time_minute);
        call_time_hour = call_time_hour + (call_time_minute / 60);

        printf("%f", call_time_hour);
    }
    else if (((day1 == 'S') && (day2 == 'a')) || ((day1 == 'S') && (day2 == 'u')))
    {
        printf("What was the duration of your call? ");
        scanf("%d", &call_duration);

        //calculate total cost of call
        cost_of_call = call_duration * 0.15;

        printf("%s %.2lf", "The cost of this call was $", cost_of_call);
    }
    calls_made--;
    printf("%d", calls_made);
}while (calls_made > 0);

So, for example, when I compile and run the program and enter "Sa" as the day that the call was made, it then moved directly to the 'calls_made--' step.

Answer 1

The problem is because previous scanf . Debug and look what characters are really scanned. I'm sure that day1 would be '\\n' .

In this case clear the input stream before scanning the day of week:

while (getchar() != '\n');