How do I fix error "use of undeclared identifier n" in C? -

i'm sure there tons of syntax/other errors, i'm trying figure out 2 it's picking on. i'm new don't know how fix undeclared identifiers. note #include <cs50.h> cs50's library.

#include <cs50.h> #include <stdio.h>  int main (void) {     int add, fee, disc;    printf("for rate tax , security deposit, type y. 10 percent off, type n:");     string name = getstring();    if (name == y)    {       printf("pretax amount: ");      scanf("%d", &fee);      printf("okay. add 10 percent tax %d.\n ", fee);       add        = (1.1 * fee);       printf("plus tax amount = %d\n", add);      printf("security deposit = 1000 dollars\n");      printf("total = (%d + 1000)", add);     }      else if (name == n)    {      printf("pretax amount: ");      scanf("%d%d", &fee, &disc);      printf("okay. minus 10 percent discount %d , add tax.\n ", fee);       add        = (0.9 * fee);      disc       = (add * 1.1);       printf("minus discount amount plus tax = %d\n", disc);      printf("security deposit = 1000 dollars\n");      printf("total = (%d + 1000)", disc);    }     return 0; } 

errors:

contractualhelper.c:10:17: error: use of undeclared identifier 'y' if (name == y)             ^ contractualhelper.c:22:22: error: use of undeclared identifier 'n' else if (name == n)                  ^ 2 errors generated. 

y , n undeclared because not have definitions.

int y; declaration, rid of error.

however, code

if (name == y) 

is comparing variable name variable y, , think want see if name contains string y.

how comparison issue.