Balancing Expressions Using Array

See Also:
C Program To Implement Postfix To Infix Conversion
C Program To Implement Postfix To Prefix Conversion
C Program To Implement Infix To Prefix Conversion
C Program To Implement Infix To Postfix Conversion
How To Evaluate Postfix Expressions
C Program To Evaluate Postfix Expression Using Array
C Program To Evaluate Postfix Expression Using Linked List
How To Balance The Given Expressions
C Program For Balancing Expressions Using Array
C Program For Balancing Expressions Using Linked List

C Program For Balancing Expressions (Parenthesis) Using Array:

---

  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  int top = -1;
  int stack[100];

  /* push the given data into the stack */
  void push(int data) {
        stack[++top] = data;
  }

  /* pop the top element from the stack */
  int pop() {
        int data;
        if (top == -1)
                return -1;
        data = stack[top];
        top--;
        return (data);
  }

  int main() {

        char str[100];

        int i, flag = 0, data = 0;

        /* get the expression from the user */

        printf("Enter ur expression:");

        fgets(str, 100, stdin);

        for (i = 0; i < strlen(str); i++) {

                /* open brace - push it into stack */

                if (str[i] == '(' || str[i] == '{'

                        || str[i] == '[') {

                                push(str[i]);

                                continue;

                }

                if (str[i] == ')' || str[i] == '}' || str[i] == ']') {

                        /* current char is close brace - so, POP */

                        data = pop();

                        if ((str[i] == ')' && data != '(') || data == -1 ||

                                (str[i] == '}' && data != '{') ||

                                        (str[i] == ']' && data != '[')) {

                                /* no matching parenthesis */

                                flag = 1;

                                break;

                        }

                }

        }

        if (flag == 1 || top > -1)

                printf("Not a balanced expression\n");

        else

                printf("Balanced Expression\n");

        return 0;

  }

  Output: (Balancing Parenthesis Example)

  jp@jp-VirtualBox:$ ./a.out
  Enter ur expression:(a+b)+{c+d(l-m)} 
  Balanced Expression