程序代码：

#include <stdio.h>

int main()
{
   
  for (;;){
    int num1,num,days,i=1;
    printf("请输入天数:");
    scanf("%d",&days);
    printf("请输入这个月第一天是星期几1-7:");
    scanf("%d",&num);
    num1=num-1;
    for (int nums=days;i<=nums;i++) {
        while (num1!=0){
            printf("\t");
            num1--;
        }
        printf("%-3d\t",i);
        if (i==7-num+1||i==14-num+1||i==21-num+1||i==28-num+1){
            printf("\n");}
   
    }
    printf("\n");}
    
    return 0;
}