C语言 二分法猜数字：无法跳出循环，部分数字ka'si

1.C语言二分法猜数字：无法跳出循环，输入部分数字会卡死
2.

#include <stdio.h>
int main() 
{
    int c;
    int a;
    int b; 
    int num; 
    char one;
    char two;
    one = 0;
    printf("Please enter your number(from '0'to'100'):");
    scanf("%d",&num);
    b=0;
    a=100;
    c = (a+b)/2.0;
    while(one!= 'y')    
         {
             KK:
             if((num >= '0')&&(num <= '100'))
              {
                RE:
                printf("%d'Y'or'N'\n",c);
                printf("Up is %d,Down is %d\n",a,b);
                one=getchar();
                  if(one == 'n')
                     {
                        GG:
                        two=getchar();
                        if(two == 'b')
                        {
                            b=c;
                            c=(a+c)/2.0;
                            goto RE;
                        }
                        else
                        if(two == 's')
                        {
                            a=c;
                            c=(b+c)/2.0;
                            goto RE;
                        }
                        else
                            {
                              printf("Please enter 'b' or 's'\n");
                              goto GG; 
                            }       
                     }
                    else
                    if((a != 'N') &&  (a !=  'Y'))
                    {
                        goto RE;
                     } 

              }
              else
              if((num <= '0')&&(num >= '100'))
              {
                goto KK;
              }
         }
    printf("The number is %d",c);
    return 0;    
}

3.

num >= '100'
这种写法不合法
应该是
int num;
scanf(("%d", &num);
if (num >= 100)
字符不能这么比较

不好比较，输入的是字符可以和字符比较，num是数字不好和字符比较！

字符和数字可以一一对应，但是，'0' 是一个字符，不是数字0，而是数字48.
C:\MinGW\test>gcc example1.c -Wall
example1.c: In function 'main':
example1.c:19:39: warning: multi-character character constant [-Wmultichar]
19 | if((num >= '0')&&(num <= '100'))
| ^~~~~
example1.c:56:40: warning: multi-character character constant [-Wmultichar]
56 | if((num <= '0')&&(num >= '100'))
| ^~~~~

        https://tool.ip138.com/ascii_code/