#include<stdio.h>

int main(void)
{
    int num;
    int week;
    int days;
    printf("enter a day\n");
    scanf_s("%d\n", &num);
    
    
    while (num <= 0)
    {
        printf("your input is wrong, try again");
        num  ;
       while (num > 0)
    
        week = num / 7;
        days = week * 7 - num;
        printf("%d days are %d week and %d days\n", &num, &week, &days);

    }
    
    return 0;
}

I try to make a loop if the num<=0 then the program will back to at begin, but it doesn't allow me to press any bottoms.

CodePudding user response：

With all respect, all your code is wrong!

First of all, don't put "%d\n" just use "%d" instead. On the same line, try to use "scanf".

Then by reading your code, what you were trying to do (I assume) is to enter a loop until the input was greater than 0, the problem is that you don't do it that way. To do so, you need to use do/while instead.

Then your second while doesn't have any curly braces. So, I did your code work just for fun :)

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

int main(void)
{
    int num = 0, week = 0, days = 0;

    do
    {
        printf("Enter a day: ");
        if(!scanf("%d", &num))
            exit(EXIT_FAILURE); // It at the time of scanning a number we fail to do so, we will exit the program execution
        if(num <= 0)
            puts("Your input is wrong! Try again.");
    } while (num <= 0);

    week = num / 7;
    days = num - (week * 7);

    printf("%d days are: %d week and %d days.\n", num, week, days);

    return 0;
}

Hope it helps.