मैं दो बार नहीं, एक बार q वर्ण दर्ज करके प्रोग्राम से कैसे बाहर निकल सकता हूं?

मैं दो बार नहीं, एक बार q वर्ण दर्ज करके प्रोग्राम से कैसे बाहर निकल सकता हूं?

मुझे एक बार फिर "q" दर्ज करने की आवश्यकता क्यों है?

मुझे लगता है कि अभिव्यक्ति || scanf("%c", &operation) ने काम नहीं किया।

/*
 * Name: Calculator.
 * Description: Calculator for simple math operations.
 *
 * Compiler: Apple LLVM version 10.0.0 (clang-1000.11.45.5).
 * Coding style: Google.
 */

#include <locale.h>
#include <math.h>
#include <stdio.h>

#define TRUE 1
#define EXIT 'q'

double add(double x, double y);
double subtract(double x, double y);
double multiply(double x, double y);
double divide(double x, double y);
double degree(double x, int y);
double sqrt(double x);          
double mod(double x, double y);
double div(double x, double y);

int main(void) {
  char *locale = setlocale(LC_ALL, "");

  printf("Examples:\n\n");

  printf("1 + 2\n");
  printf("1 - 2\n");
  printf("1 * 2\n");
  printf("1 / 2\n");
  printf("1 ^ 2\n");
  printf("(sqrt): s 2\n");
  printf("(mod): 1 m 2\n");
  printf("(div): 1 d 2\n\n");

  printf("Input for exit: \"q\"\n\n");

  while (TRUE) {
    double x, y;
    char operation;

    scanf("%lf %c %lf", &x, &operation, &y) ||
        scanf("%c %lf", &operation, &x) || scanf("%c", &operation);

    switch (operation) {
      case ' ':
        break;

      case '\n':
        break;

      case '+':
        printf("Result = %.2lf\n", add(x, y));
        break;

      case '-':
        printf("Result = %.2lf\n", subtract(x, y));
        break;

      case '*':
        printf("Result = %.2lf\n", multiply(x, y));
        break;

      case '/':
        if (y != 0) {
          printf("Result = %.2lf\n", divide(x, y));
        } else {
          printf("\nError!.\n");
        }
        break;

      case '^':
        printf("Result = %.2lf\n", degree(x, y));
        break;

      case 's':
        printf("Result = %.2lf\n", sqrt(x));
        break;

      case 'm':
        printf("Result = %.2lf\n", divide(x, y));
        break;

      case 'd':
        printf("Result = %.2lf\n", divide(x, y));
        break;

      case EXIT:
        printf("Input symbol \"%c\"\nExit...\n", EXIT);
        return 0;
    }
  }

  return 0;
}

double add(double x, double y) { return (x + y); }

double subtract(double x, double y) { return (x - y); }

double multiply(double x, double y) { return (x * y); }

double divide(double x, double y) { return (x / y); }

double degree(double x, int y) {
  int response = 1;
  while (y) {
    if (y & 1) response *= x;
    x *= x;
    y >>= 1;
  }
  return response;
}