Task: Balanced brackets


C++: #include <algorithm>
#include <iostream>
#include <string>

std::string generate(int n, char left = '[', char right = ']')
{
    std::string str(std::string(n, left) + std::string(n, right));
    std::random_shuffle(str.begin(), str.end());
    return str;
}

bool balanced(const std::string &str, char left = '[', char right = ']')
{
    int count = 0;
    for (std::string::const_iterator it = str.begin(); it != str.end(); ++it)
    {
        if (*it == left)
            count++;
        else if (*it == right)
            if (--count < 0) return false;
    }
    return count == 0;
}

int main()
{
    srand(time(NULL)); 
    for (int i = 0; i < 9; ++i)
    {
        std::string s(generate(i));
        std::cout << (balanced(s) ? " ok: " : "bad: ") << s << "\n";
    }
}








COBOL:        IDENTIFICATION DIVISION.
       PROGRAM-ID. test-balanced-brackets.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  True-Val  CONSTANT 0.
       01  False-Val CONSTANT 1.

       LOCAL-STORAGE SECTION.
       01  current-time        PIC 9(10).

       01  bracket-type        PIC 9.
           88 add-open-bracket VALUE 1.

       01  bracket-string-area.
           03  bracket-string  PIC X(10) OCCURS 10 TIMES.

       01  i                   PIC 999.
       01  j                   PIC 999.

       PROCEDURE DIVISION.
           
           MOVE FUNCTION CURRENT-DATE (7:10) TO current-time
           MOVE FUNCTION RANDOM(current-time) TO current-time


           
           PERFORM VARYING i FROM 1 BY 1 UNTIL 10 < i
               PERFORM VARYING j FROM 1 BY 1 UNTIL i < j
                   COMPUTE bracket-type =
                       FUNCTION REM(FUNCTION RANDOM * 1000, 2)

                   IF add-open-bracket
                       MOVE "[" TO bracket-string (i) (j:1)
                   ELSE
                       MOVE "]" TO bracket-string (i) (j:1)
                   END-IF
               END-PERFORM
           END-PERFORM

           
           PERFORM VARYING i FROM 1 BY 1 UNTIL 10 < i
               CALL "check-if-balanced" USING bracket-string (i)
               IF RETURN-CODE = True-Val
                   DISPLAY FUNCTION TRIM(bracket-string (i))
                       " is balanced."
               ELSE
                   DISPLAY FUNCTION TRIM(bracket-string (i))
                       " is not balanced."
               END-IF
           END-PERFORM

           GOBACK
           .

       END PROGRAM test-balanced-brackets.

       IDENTIFICATION DIVISION.
       PROGRAM-ID. check-if-balanced.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  True-Val  CONSTANT 0.
       01  False-Val CONSTANT 1.

       LOCAL-STORAGE SECTION.
       01  nesting-level  PIC S999.
       01  i              PIC 999.

       LINKAGE SECTION.
       01  bracket-string PIC X(100).

       PROCEDURE DIVISION USING bracket-string.
           PERFORM VARYING i FROM 1 BY 1
                   UNTIL (100 < i)
                      OR (bracket-string (i:1) = SPACE)
                      OR (nesting-level < 0)
               IF bracket-string (i:1) = "["
                   ADD 1 TO nesting-level
               ELSE
                   SUBTRACT 1 FROM nesting-level
                   IF nesting-level < 0
                       MOVE False-Val TO RETURN-CODE 
                       GOBACK
                   END-IF
               END-IF
           END-PERFORM
           
           IF nesting-level = 0
               MOVE True-Val TO RETURN-CODE
           ELSE
               MOVE False-Val TO RETURN-CODE
           END-IF
           
           GOBACK
           . 

       END PROGRAM check-if-balanced.