在Java中生成空白

Question

您好我正在尝试生成空格，以便在startDay == 2或更多时 第一行有空格。该程序应该模拟日历 因此，例如，如果有标题（星期一，星期二等），空格将允许“1”（即日期 1）位于正确的日< / em>的

import java.io.*;
public class Lab_4 {

  public static void main(String[] args) { 
    InputStreamReader input = new InputStreamReader(System.in);
    BufferedReader reader = new BufferedReader(input);

Integer daysInMonth=31;
Integer startDay = 1;
int daysInWeek;

// we catch IO exceptions if any are thrown.
try {  
  System.out.println("how many days are in the month?");
  daysInMonth = Integer.parseInt(reader.readLine());
  //validate input
  while((daysInMonth >= 32) || (daysInMonth < 28)){
    System.out.println("There can't be more than 31 days or less than 28 days, enter a 
     valid number");
    daysInMonth = Integer.parseInt(reader.readLine());
  }

  System.out.println("what is the starting day of the month? 1=sun... 7=sat");
  startDay = Integer.parseInt(reader.readLine());
  //validate input
  while((startDay > 7)){
    System.out.println("There cannot be more days than 7 days in a week, enter a valid 
number");
    startDay = Integer.parseInt(reader.readLine());
  }
}catch (IOException e){
  System.out.println("Error reading from user");     
}

daysInWeek = 1;    


//print every seven days to a new line of calender
if (startDay == 1) {
  for (int i = daysInWeek; i <= (daysInMonth); i++) {
    daysInWeek ++;
    System.out.printf("%-2d   ",i);
    if ( daysInWeek ==7) { 
      System.out.println();
      daysInWeek = 1;
    }
  }
}

//create blank space if start day is 2 
if (startDay == 2) {
  for (int i = daysInWeek; i <= (daysInMonth); i++) {
    daysInWeek ++;

    System.out.print("  ");
    System.out.printf("%-2d   ",i);
    if ( daysInWeek ==7) { 
      System.out.println();
      daysInWeek = 1;
        }
      }
    }

  }
}

Answer 1

从您的行开始

daysInWeek = 1;    

尝试更改为

daysInWeek = 1; // Start point...
int offSet = 0; // an offset of 0 == SATURDAY
if (startDay != 7) {
  offSet = (startDay == 1) ? 6 : startDay - 1; // SUNDAY goes far right.
}

for (int i = 0; i < offSet; i++) { // Here's that spacing you wanted.
  System.out.print("    ");
}

// print every seven days to a new line of calender
for (int i = 1; i <= (daysInMonth); i++) {
  System.out.printf("%-2d  ", i);
  if ((daysInWeek + offSet) % 7 == 0) { // Add the offset, perform mod 7.
    System.out.println();
  }
  daysInWeek++;
}