assignment of read-only parameter N

[gaotianyu]

Here is all my code but I get a error with N/=10
it says:assignment of read-only parameter N
I don't know how to deal with it

#include<stdio.h>
#include<math.h>
int number(const int N);
int main()
{
    int n1,n2,i,cnt;
    scanf("%d %d",&n1,&n2);
    cnt=0;
    for(i=n1;i<n2;i++)
    {
        if(number(i))
        cnt++;
    }
    printf("cnt=%d\n",cnt);
    return 0;
 } 
 
 int number(const int N)
 {
     int x,y;
     int num[50]={0};
     int b=10,count=0;
     for(int j=1;;j++)              //计算输入数值的总位数 
     {
         if(N%b!=0) count+=1;
         else break;
         b/=10;
    }
     for(int y=0;y<count;y++)      //将每一位 分别存储在数组中 
     {
         int c=N%b;
         num[y]=c;
         N/=10;
    }
     for(y=0, x=count-1;y<count,x>=0;y++,x--)
     {
         if((num[y]==num[x])&&(sqrt(N)==(int)sqrt(N))) return 1;
         else return 0;
     }
 }

[Frinavale]

Your variable N is a const.

A constant, like a variable, is a memory location where a value can be stored. Unlike variables, constants never change in value.

Therefore, you cannot do this:

N/=10;

Or this:

N=N/10;

Because you can never set N after it is initialized.

[donbock]

What do you hope to accomplish by declaring int number(const int N)?
C is a call-by-value language. From the caller’s point-of-view, its arguments are safe from alteration by number regardless of const in the declaration.

const can be meaningful with pointer arguments but that isn’t the case here.