Language: C

#include<stdio.h>
int main(void){
  char moji[1000]
  int i,j;
  scanf("%s\n",&moji[i]);
  for(j=1; j=<i; j++){
    
  if(moji[i]==A){
      moji[i]=X;
  }else if(moji[i]==B){
      moji[i]=Y;
  }else if(moji[i]==C){
      moji[i]=Z;
  }else if(moji[i]==D){
      moji[i]=A;
  }else if(moji[i]==E){
      moji[i]=B;
  }else if(moji[i]==F){
      moji[i]=C;
  }else if(moji[i]==G){
      moji[i]=D;
  }else if(moji[i]==H){
      moji[i]=E;
  }else if(moji[i]==I){
      moji[i]=F;
  }else if(moji[i]==J){
      moji[i]=G;
  }else if(moji[i]==K){
      moji[i]=H;
  }else if(moji[i]==L){
      moji[i]=I;
  }else if(moji[i]==M){
      moji[i]=J;
  }else if(moji[i]==N){
      moji[i]=K;
  }else if(moji[i]==O)[
      moji[i]=L;
  }else if(moji[i]==P){
      moji[i]=M;
  }else if(moji[i]==Q){
      moji[i]=N;
  }else if(moji[i]==R){
      moji[i]=O;
  }else if(moji[i]==S){
      moji[i]=P;
  }else if(moji[i]==T){
      moji[i]=Q;
  }else if(moji[i]==U){
      moji[i]=R;
  }else if(moji[i]==V){
      moji[i]=S;
  }else if(moji[i]==W){
      moji[i]=T;
  }else if(moji[i]==X){
      moji[i]=U;
  }else if(moji[i]==Y){
      moji[i]=V;
  }else if(moji[i]==Z){
      moji[i]=W;
  }
  printf("%s",moji[i]);
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:3:18: error: expected ';' before 'int'
    3 |   char moji[1000]
      |                  ^
      |                  ;
    4 |   int i,j;
      |   ~~~             
main.c:5:17: error: 'moji' undeclared (first use in this function)
    5 |   scanf("%s\n",&moji[i]);
      |                 ^~~~
main.c:5:17: note: each undeclared identifier is reported only once for each function it appears in
main.c:6:14: error: expected expression before '<' token
    6 |   for(j=1; j=<i; j++){
      |              ^
main.c:8:15: error: 'A' undeclared (first use in this function)
    8 |   if(moji[i]==A){
      |               ^
main.c:9:15: error: 'X' undeclared (first use in this function)
    9 |       moji[i]=X;
      |               ^
main.c:10:21: error: 'B' undeclared (first use in this function)
   10 |   }else if(moji[i]==B){
      |                     ^
main.c:11:15: error: 'Y' undeclared (first use in this function)
   11 |       moji[i]=Y;
      |               ^
main.c:12:21: error: 'C' undeclared (first use in this function)
   12 |   }else if(moji[i]==C){
      |                     ^
main.c:13:15: error: 'Z' undeclared (first use in this function)
   13 |       moji[i]=Z;
      |               ^
main.c:14:21: error: 'D' undeclared (first use in this function)
   14 |   }else if(moji[i]==D){
      |                     ^
main.c:16:21: error: 'E' undeclared (first use in this function)
   16 |   }else if(moji[i]==E){
      |                     ^
main.c:18:21: error: 'F' undeclared (first use in this function)
   18 |   }else if(moji[i]==F){
      |                     ^
main.c:20:21: error: 'G' undeclared (first use in this function)
   20 |   }else if(moji[i]==G){
      |                     ^
main.c:22:21: error: 'H' undeclared (first use in this function)
   22 |   }else if(moji[i]==H){
      |                     ^
main.c:24:21: error: 'I' undeclared (first use in this function)
   24 |   }else if(moji[i]==I){
      |                     ^
main.c:26:21: error: 'J' undeclared (first use in this function)
   26 |   }else if(moji[i]==J){
      |                     ^
main.c:28:21: error: 'K' undeclared (first use in this function)
   28 |   }else if(moji[i]==K){
      |                     ^
main.c:30:21: error: 'L' undeclared (first use in this function)
   30 |   }else if(moji[i]==L){
      |                     ^
main.c:32:21: error: 'M' undeclared (first use in this function)
   32 |   }else if(moji[i]==M){
      |                     ^
main.c:34:21: error: 'N' undeclared (first use in this function)
   34 |   }else if(moji[i]==N){
      |                     ^
main.c:36:21: error: 'O' undeclared (first use in this function)
   36 |   }else if(moji[i]==O)[
      |                     ^
main.c:36:23: error: expected expression before '[' token
   36 |   }else if(moji[i]==O)[
      |                       ^
main.c:37:17: error: expected ';' before '}' token
   37 |       moji[i]=L;
      |                 ^
      |                 ;
   38 |   }else if(moji[i]==P){
      |   ~              
main.c:38:4: error: 'else' without a previous 'if'
   38 |   }else if(moji[i]==P){
      |    ^~~~
main.c:38:21: error: 'P' undeclared (first use in this function)
   38 |   }else if(moji[i]==P){
      |                     ^
main.c:40:21: error: 'Q' undeclared (first use in this function)
   40 |   }else if(moji[i]==Q){
      |                     ^
main.c:42:21: error: 'R' undeclared (first use in this function)
   42 |   }else if(moji[i]==R){
      |                     ^
main.c:44:21: error: 'S' undeclared (first use in this function)
   44 |   }else if(moji[i]==S){
      |                     ^
main.c:46:21: error: 'T' undeclared (first use in this function)
   46 |   }else if(moji[i]==T){
      |                     ^
main.c:48:21: error: 'U' undeclared (first use in this function)
   48 |   }else if(moji[i]==U){
      |                     ^
main.c:50:21: error: 'V' undeclared (first use in this function)
   50 |   }else if(moji[i]==V){
      |                     ^
main.c:52:21: error: 'W' undeclared (first use in this function)
   52 |   }else if(moji[i]==W){
      |                     ^