CS50, vigenere.c lack of argv -

i tried check50, , got message command down below.

#include<cs50.h> #include<stdio.h> #include<ctype.h> #include<string.h> #include<stdlib.h> #include<math.h>  int main(int argc, string argv[]) {     string = argv[1];     int s = strlen(a);     if(s == 0)     {     printf("no keyword entered\n");     return 1;     }     for(int k = 0; k < s; k++)     {     if(!isalpha(a[k]))     {     printf("keyword not alphabetical\n");     return 1;     }     }     string t = getstring();     int = 0;     int x = 0;     int v = 65;     for(int n = strlen(t); < n; ++)     {         if(isalpha(t[i]))         {            if(isupper(t[i]))            {               if(isupper(t[i]))               {               if(islower(a[x]))               {               v = v + 32;               }               int p = a[x];               p = p -v;               int 1 =t[i];               1 = 1 - 65;               int b = (1+ p[s%x]%26;               b = b + 65;               char c = b;               printf("%c", c);               x = x+1;              }             if(islower(t[i]))             {                int p = a[x];                p = p - v;                int 1 = t[i];                1 = 1-97;                int b =(1 +p[s%x]%26;                b = b + 97;                char c = b;                printf("%c", c);                x = x + 1;               }             }             else             {             printf)"%c", t[i]);             }          }          printf('\n');      }              

error message: :| encrypts "a" "a" using "a" keyword :| encrypts "world, hello!" "xoqmd, rby gflkp!" using "baz" keyword :| encrypts "barfoo" "caqgon" using "baz" keyword :| encrypts "barfoo" "caqgon" using "baz" keyword :| handles lack of argv[1] :| handles argc > 2 :| rejects "hax0r2" keyword

how fix all?