关于c语言头文件的问题

我想把下面这三个都用到头文件改怎么弄呢，有酬

1：

int main(void)
{
    int num;
    int ans;
    printf("enter a number:");
    scanf_s("%d", &num);

    //a loop for an array
    for (ans = num; ans<= num+largevalue; ans++)

        //display the array
    printf("this is  you looking for:%d\n", ans);
    

    return 0;

2：
int main(void)
{

    int lower, upper;
    double squareroot;
    int square;
    int cube;
    // input a limit value
    printf("Enter the Lower Limit: ");
    scanf_s("%d", &lower);
    printf("Enter the Upper Limit: ");
    scanf_s("%d", &upper);
    if (lower < 0 || upper >50)
    {
        printf("The input value is invalid");
    }

    // a range
    else
    {
        printf("*base number*  |  *square root*  |   *square*    | *cube*\n");

        for (int i = lower; i <= upper; i++)
        {
            // the formular to find the squareroot, square, cube
            squareroot = sqrt(i);
            square = i * i;
            cube = i * i * i;
            printf("*%d*            |    *%f*   |       *%ld*     |   *%ld*\n",
                i, squareroot, square, cube);
        }
    }
    

    return 0;
}

3：
int main(void)
{
    while (1)
    {
        int num;
        int days;
        int week;
        printf("enter a day\n"); //input the value
        scanf_s("%d", &num);

        if (num > 0)
        {
            //convert the days to weeks and days
            week = num / 7;
            days = num - week * 7;


            printf("%d days are %d weeks, %d days.\n", num, week, days);
            continue;
        }
        //print result
        printf("Invalid input! Please try again.\n");


        //break out of loop
        break;
    }
    return 0;
}

我想要达到的结果（用到头文件都行）

img

img

img