Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  char C;
  cin>>C;
  if(C=='a'){
    cout<<"b"<<endl;
  }
  if else(C=='b'){
    cout<<"c"<<endl;
  }
  if else(C=='c'){
    cout<<"d"<<endl;
  }
  if else(C=='d'){
    cout<<"e"<<endl;
  }
  if else(C=='e'){
    cout<<"f"<<endl;
  }
  if else(C=='f'){
    cout<<"g"<<endl;
  }
  if else(C=='g'){
    cout<<"h"<<endl;
  }
  if else(C=='h'){
    cout<<"i"<<endl;
  }
  if else(C=='i'){
    cout<<"j"<<endl;
  }
  if else(C=='j'){
    cout<<"k"<<endl;
  }
  if else(C=='k'){
    cout<<"l"<<endl;
  }
  if else(C=='l'){
    cout<<"m"<<endl;
  }
  if else(C=='m'){
    cout<<"n"<<endl;
  }
  if else(C=='n'){
    cout<<"o"<<endl;
  }
  if else(C=='o'){
    cout<<"p"<<endl;
  }
  if else(C=='p'){
    cout<<"q"<<endl;
  }
  if else(C=='q'){
    cout<<"r"<<endl;
  } 
  if else(C=='r'){
    cout<<"s"<<endl;
  }
  if else(C=='s'){
    cout<<"t"<<endl;
  }
  if else(C=='t'){
    cout<<"u"<<endl;
  }
  if else(C=='u'){
    cout<<"v"<<endl;
  }
  if else(C=='v'){
    cout<<"w"<<endl;
  }
  if else(C=='w'){
    cout<<"x"<<endl;
  }
  if else(C=='x'){
    cout<<"y"<<endl;
  }
  if else(C=='y'){
    cout<<"z"<<endl;
  }
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:6: error: expected '(' before 'else'
    9 |   if else(C=='b'){
      |      ^~~~
      |      (
a.cc:12:6: error: expected '(' before 'else'
   12 |   if else(C=='c'){
      |      ^~~~
      |      (
a.cc:15:6: error: expected '(' before 'else'
   15 |   if else(C=='d'){
      |      ^~~~
      |      (
a.cc:18:6: error: expected '(' before 'else'
   18 |   if else(C=='e'){
      |      ^~~~
      |      (
a.cc:21:6: error: expected '(' before 'else'
   21 |   if else(C=='f'){
      |      ^~~~
      |      (
a.cc:24:6: error: expected '(' before 'else'
   24 |   if else(C=='g'){
      |      ^~~~
      |      (
a.cc:27:6: error: expected '(' before 'else'
   27 |   if else(C=='h'){
      |      ^~~~
      |      (
a.cc:30:6: error: expected '(' before 'else'
   30 |   if else(C=='i'){
      |      ^~~~
      |      (
a.cc:33:6: error: expected '(' before 'else'
   33 |   if else(C=='j'){
      |      ^~~~
      |      (
a.cc:36:6: error: expected '(' before 'else'
   36 |   if else(C=='k'){
      |      ^~~~
      |      (
a.cc:39:6: error: expected '(' before 'else'
   39 |   if else(C=='l'){
      |      ^~~~
      |      (
a.cc:42:6: error: expected '(' before 'else'
   42 |   if else(C=='m'){
      |      ^~~~
      |      (
a.cc:45:6: error: expected '(' before 'else'
   45 |   if else(C=='n'){
      |      ^~~~
      |      (
a.cc:48:6: error: expected '(' before 'else'
   48 |   if else(C=='o'){
      |      ^~~~
      |      (
a.cc:51:6: error: expected '(' before 'else'
   51 |   if else(C=='p'){
      |      ^~~~
      |      (
a.cc:54:6: error: expected '(' before 'else'
   54 |   if else(C=='q'){
      |      ^~~~
      |      (
a.cc:57:6: error: expected '(' before 'else'
   57 |   if else(C=='r'){
      |      ^~~~
      |      (
a.cc:60:6: error: expected '(' before 'else'
   60 |   if else(C=='s'){
      |      ^~~~
      |      (
a.cc:63:6: error: expected '(' before 'else'
   63 |   if else(C=='t'){
      |      ^~~~
      |      (
a.cc:66:6: error: expected '(' before 'else'
   66 |   if else(C=='u'){
      |      ^~~~
      |      (
a.cc:69:6: error: expected '(' before 'else'
   69 |   if else(C=='v'){
      |      ^~~~
      |      (
a.cc:72:6: error: expected '(' before 'else'
   72 |   if else(C=='w'){
      |      ^~~~
      |      (
a.cc:75:6: error: expected '(' before 'else'
   75 |   if else(C=='x'){
      |      ^~~~
      |      (
a.cc:78:6: error: expected '(' before 'else'
   78 |   if else(C=='y'){
      |      ^~~~
      |      (