怎么错了，求解

#include<stdio.h>
#include<stdlib.h>
int main ()
{
    char b[265],q[999];
    int c=1,n;
    int i;
    scanf("%d",&n);
    for(char a=97;a<=122;a++)
            {
                b[c]=a;
                c++; 
            }
    c=1;
    for (i=1;i<=n;i++)
     {
             scanf ("%c",&q[i]);
     }
     while (i<=n) 
     {    
             i=1;         
             c=1;
             while (b[c]!=q[i])  
             {   
                 if (c>26) {c=1;}
                 c++;
             }
         q[i]=b[c+n];
         if (c>26) {c=1;}
         printf ("%c",q[i]);
         n++;
         i++;
     }
     system("pause");
     return 0;
}