Language: Java

import java.util.Scanner;

class Main {
  public static void main(String[] args) {
    Scanner stdIn = new Scanner(System.in);
    System.out.println("コインの数");
  do{

    do {
      System.out.print("500円玉：");
      int A = stdIn.nextInt();
    } while (A < 0 || A > 50);
    do {
      System.out.print("100円玉：");
      int B = stdIn.nextInt();
    } while (B < 0 || B > 50);
    do {
      System.out.print(" 50円玉：");
      int C = stdIn.nextInt();
    } while (C < 0 || C > 50);

  } while (A + B + C == 0);

    do {
    System.out.print("X円にする：");
    int X = stdIn.nextInt();
  } while (X < 50 || X > 20000);

    int count = 0; int sum = 0;
    for (int i = 0; i < A ; i++) {
      int a = 500 * i;
      sum = a;
      if (sum > X) {
        break;
      } else if (sum == X) {
        count++;
        break;
      }

      for (int j = 0; j < B ; j++) {
        int b = 100 * j;
        sum = a + b;
        if (sum > X) {
          break;
        } else if (sum == X) {
          count++;
          break;
        }

        for (int k = 0; k < C ; k++) {
          int c = 50 * k;
          sum = a + b + c;
          if (sum > X) {
            break;
          } else if (sum == X) {
            count++;
            break;
          }
        }
      }
    }

  System.out.println(count);
  }
}


Compiler output:
Main.java:12: error: cannot find symbol
    } while (A < 0 || A > 50);
             ^
  symbol:   variable A
  location: class Main
Main.java:12: error: cannot find symbol
    } while (A < 0 || A > 50);
                      ^
  symbol:   variable A
  location: class Main
Main.java:16: error: cannot find symbol
    } while (B < 0 || B > 50);
             ^
  symbol:   variable B
  location: class Main
Main.java:16: error: cannot find symbol
    } while (B < 0 || B > 50);
                      ^
  symbol:   variable B
  location: class Main
Main.java:20: error: cannot find symbol
    } while (C < 0 || C > 50);
             ^
  symbol:   variable C
  location: class Main
Main.java:20: error: cannot find symbol
    } while (C < 0 || C > 50);
                      ^
  symbol:   variable C
  location: class Main
Main.java:22: error: cannot find symbol
  } while (A + B + C == 0);
           ^
  symbol:   variable A
  location: class Main
Main.java:22: error: cannot find symbol
  } while (A + B + C == 0);
               ^
  symbol:   variable B
  location: class Main
Main.java:22: error: cannot find symbol
  } while (A + B + C == 0);
                   ^
  symbol:   variable C
  location: class Main
Main.java:27: error: cannot find symbol
  } while (X < 50 || X > 20000);
           ^
  symbol:   variable X
  location: class Main
Main.java:27: error: cannot find symbol
  } while (X < 50 || X > 20000);
                     ^
  symbol:   variable X
  location: class Main
Main.java:30: error: cannot find symbol
    for (int i = 0; i < A ; i++) {
                        ^
  symbol:   variable A
  location: class Main
Main.java:33: error: cannot find symbol
      if (sum > X) {
                ^
  symbol:   variable X
  location: class Main
Main.java:35: error: cannot find symbol
      } else if (sum == X) {
                        ^
  symbol:   variable X
  location: class Main
Main.java:40: error: cannot find symbol
      for (int j = 0; j < B ; j++) {
                          ^
  symbol:   variable B
  location: class Main
Main.java:43: error: cannot find symbol
        if (sum > X) {
                  ^
  symbol:   variable X
  location: class Main
Main.java:45: error: cannot find symbol
        } else if (sum == X) {
                          ^
  symbol:   variable X
  location: class Main
Main.java:50: error: cannot find symbol
        for (int k = 0; k < C ; k++) {
                            ^
  symbol:   variable C
  location: class Main
Main.java:53: error: cannot find symbol
          if (sum > X) {
                    ^
  symbol:   variable X
  location: class Main
Main.java:55: error: cannot find symbol
          } else if (sum == X) {
                            ^
  symbol:   variable X
  location: class Main
20 errors