只输入b能算才怪

我稍做修改了下，好像你输入字母时格式有问题，要用英文输入状态，还有就是代码不规范，自己再好好的修改，你会很成功的！

#include<stdio.h>

int main()
{
    int a;
    float b,c,d;
   
    printf("======================简易两数加减乘除计算器==========================\n\n\n");
    printf("======================请选择运算方式==========================\n\n\n");
    printf("1.加     2.减      3.乘      4.除     5.大小比较    6.退出\n\n");
    printf("亲：请选择你的运算符\n");
    scanf("%d",&a);

    switch( a )
    {
        case 1:
            printf("请输入加数b的值：\n");
            scanf("%f", &b);
            printf("请输入加数c的值：\n");
            scanf("%f", &c);
            d = b + c;
            printf("和为：%.2\n",d);
            break;
        case 2:
            printf("请输入被减数b的值：\n");
            scanf("%f",&b);
            printf("请输入减数c的值：\n");
            scanf("%f",&c);
            d = b - c;
            printf("差为：%.2f\n",d);
            break;
        case 3:
            printf("请输入乘数b的值：\n");
            scanf("%f",&b);
            printf("请输入乘数c的值：\n");
            scanf("%f",&c);
            d = b * c;
            printf("积为：%.2f\n",d);
            break;
        case 4:
            printf("请输入被除数b的值：\n");
            scanf("%f",&b);
            printf("请输入除数c的值：\n");
            scanf("%f",&c);
            d = b / c;
            printf("商为：%.2f\n",d);
            break;
        case 5:
            printf("请输入第一个数b的值：\n");
            scanf("%f",b);
            printf("请输入第二个数c的值：\n");
            scanf("%f",c);
            d = b > c ? b : c;
            printf("较大值为：%.2f\n", d);
        case 6:
            return;
       default:
            printf("您输入的数据有错误！请重新选择\n");
            break;
   }
}

这个没有写出大小比较的选项啊

#include<stdio.h>
int main()
{
     int a,b,c,d;
  printf("======================简易两数加减乘除计算器==========================\n\n\n");
  printf("======================请选择运算方式==========================\n\n\n");
  for(int i=1;i<=5;i++){
  printf("[1]加法\n");
  printf("[2]减法\n");
  printf("[3]乘法\n");
  printf("[4]除法\n");
  printf("[0]退出计算器\n");
  printf("请输入选择：");
  scanf("%d",&a);
  switch(a)
  {
      case 1:
      printf("请输入数字，用空格隔开：\n");
      scanf("%d%d",&a,&b);
        d=a+b;
    printf("%d+%d=%d",a,b,d);
      break;
      case 2:
      printf("请输入数字，用空格隔开：\n");
      scanf("%d%d",&a,&b);
    d=a-b;
    printf("%d-%d=%d",a,b,d);
      break;
      case 3:
      printf("请输入数字，用空格隔开：\n");
      scanf("%d%d",&a,&b);
    d=a*b;
    printf("%d*%d=%d",a,b,d);
      break;
      case 4:
      printf("请输入数字，用空格隔开：\n");
      scanf("%d%d",&a,&b);
    d=1.0*a/b;
    printf("%d/%d=%d",a,b,d);
      break;
      default:
      printf("您输入的数据有错误！请重新选择\n");
  }}
  return 0;
}