Language: C

#include<stdio.h>

int main (void){
  	char b;
  	scanf("%c",&b);
	char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
    char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
    for(int i=0;i<26;i++){
 		if(a[i]=b){
          printf("a\n");
          return 0;
        }  
      if(A[i]=b){
          printf("A\n");
          return 0;
        }  
}

Compiler output:
main.c: In function 'main':
main.c:6:21: error: initialization of 'char' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                     ^
main.c:6:21: note: (near initialization for 'a[0]')
main.c:6:25: error: 'c' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                         ^
main.c:6:25: note: each undeclared identifier is reported only once for each function it appears in
main.c:6:27: error: 'd' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                           ^
main.c:6:29: error: 'e' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                             ^
main.c:6:31: error: 'f' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                               ^
main.c:6:33: error: 'g' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                 ^
main.c:6:35: error: 'h' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                   ^
main.c:6:37: error: 'i' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                     ^
main.c:6:39: error: 'j' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                       ^
main.c:6:41: error: 'k' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                         ^
main.c:6:43: error: 'l' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                           ^
main.c:6:45: error: 'm' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                             ^
main.c:6:47: error: 'n' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                               ^
main.c:6:49: error: 'o' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                 ^
main.c:6:51: error: 'p' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                   ^
main.c:6:53: error: 'q' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                     ^
main.c:6:55: error: 'r' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                       ^
main.c:6:57: error: 's' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                         ^
main.c:6:59: error: 't' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                           ^
main.c:6:61: error: 'y' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                             ^
main.c:6:63: error: 'v' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                               ^
main.c:6:65: error: 'w' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                                 ^
main.c:6:67: error: 'x' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                                   ^
main.c:6:71: error: 'z' undeclared (first use in this function)
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                                                                       ^
main.c:6:72: error: expected '}' before ')' token
    6 |         char a[26]={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,y,v,w,x,y,z);
      |                    ~                                                   ^
main.c:6:72: error: expected ',' or ';' before ')' token
main.c:7:17: error: initialization of 'char' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                 ^
main.c:7:17: note: (near initialization for 'A[0]')
main.c:7:19: error: 'B' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                   ^
main.c:7:21: error: 'C' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                     ^
main.c:7:23: error: 'D' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                       ^
main.c:7:25: error: 'E' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                         ^
main.c:7:27: error: 'F' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                           ^
main.c:7:29: error: 'G' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                             ^
main.c:7:31: error: 'H' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                               ^
main.c:7:33: error: 'I' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                 ^
main.c:7:35: error: 'J' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                   ^
main.c:7:37: error: 'K' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                     ^
main.c:7:39: error: 'L' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                       ^
main.c:7:41: error: 'M' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                         ^
main.c:7:43: error: 'N' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                           ^
main.c:7:45: error: 'O' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                             ^
main.c:7:47: error: 'P' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                               ^
main.c:7:49: error: 'Q' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                 ^
main.c:7:51: error: 'R' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                   ^
main.c:7:53: error: 'S' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                     ^
main.c:7:55: error: 'T' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                       ^
main.c:7:57: error: 'U' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                         ^
main.c:7:59: error: 'V' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                           ^
main.c:7:61: error: 'W' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                             ^
main.c:7:63: error: 'X' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                               ^
main.c:7:65: error: 'Y' undeclared (first use in this function)
    7 |     char A[26]={A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z);
      |                                                                 ^
mai