# include <stdio.h>

int main ()
{
    int a,x, b;//x 为年份
    printf ("请输入年份和月份\n");
  scanf ("%d%d",&x,&a);
      if (a = 2)//闰年分开处理
    if (x%4==0&&x%100==0)
       {
          b = 29;}
    else
       {
           b = 28;}

}
    if (a = 1 || 3 || 5 || 7 || 8 || 10 || 12)
          {
           b = 31;}
   if (a =  4 || 6 || 9 || 11 )
        {
        b = 30;}

    printf ("%d",b);
  return 0;

}
各位大佬能帮我找一下错误吗？可以编译，但结果不对

// if (a = 1 || 3 ||.....)
 if (a==1 || a==3 || a==......)

1.=赋值  ==等于 2. ||两边是非0数 判断为真      
 试试这个#include <stdio.h>
int main ()
{
    int a,x, b;            //x 为年份
    printf ("请输入年份和月份\n");
  scanf ("%d%d",&x,&a);
      if (a == 2)       //闰年分开处理
      {
          if (x%4==0&&x%100==0)
       {
          b = 29;}
    else
       {
           b = 28;
        }
      }
    if (a == 1 || a==3 ||a== 5 ||a== 7 || a==8 || a==10 ||a==12)
          {
           b = 31;}
   if (a ==  4 ||a== 6 ||a== 9 ||a== 11)
        {
        b = 30;
   }
    printf ("%d",b);
  return 0;
}
 

1.=赋值  ==等于 2. ||两边是非0数 判断为真      
 试试这个#include <stdio.h>
int main ()
{
    int a,x, b;            //x 为年份
    printf ("请输入年份和月份\n");
  scanf ("%d%d",&x,&a);
      if (a == 2)       //闰年分开处理
      {
          if (x%4==0&&x%100==0)
       {
          b = 29;}
    else
       {
           b = 28;
        }
      }
    if (a == 1 || a==3 ||a== 5 ||a== 7 || a==8 || a==10 ||a==12)
          {
           b = 31;}
   if (a ==  4 ||a== 6 ||a== 9 ||a== 11)
        {
        b = 30;
   }
    printf ("%d",b);
  return 0;
}
 

谢各位大佬了