Switch statement closing [closed] - c

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I am writing a switch statement that is supposed to act like a simple calculator, and when I select case 5 it's supposed to toggle between single and double precision. However when I select case 5, I get Calculator now works with double precision. and it exits the program. It was actually working before until I added case 6 which is supposed to be the one that exit's the program.
int opt;
float first, second, sum, difference, product, quotient;
double first_d, second_d, sum_d, difference_d, product_d, quotient_d;
char ch;
printf("This program implements a calculator. Options:\n");
printf(" 1 - addition\n 2 - subtraction\n 3 - multiplication\n 4 - division\n");
printf(" 5 - toggle precision\n 6 - exit program");
ch = getchar();
for(;;) {
printf("Please enter your option:");
scanf("%d", &opt);
switch (opt) {
case 1:
printf("Enter first term:");
scanf("%f", &first);
printf("Enter second term:");
scanf("%f", &second);
sum = first + second;
printf("The sum is: %f\n", sum);
break;
case 2:
printf("Enter first term:");
scanf("%f", &first);
printf("Enter second term:");
scanf("%f", &second);
difference = first - second;
printf("the difference is: %f\n", difference);
break;
case 3:
printf("Enter first term:");
scanf("%f", &first);
printf("Enter second term:");
scanf("%f", &second);
product = first * second;
printf("The product is: %f\n", product);
break;
case 4:
printf("Enter first term:");
scanf("%f", &first);
printf("Enter second term:");
scanf("%f", &second);
quotient = first/ (float)second;
printf("The quotient is: %f\n", quotient);
if(second == 0){
printf("Cannot divide by 0!\n");
}
break;
case 5:
if(ch != '1' && '2' && '3' && '4' && '6'){
printf("Calculator now works with double precision.\n");
switch (opt) {
case 1:
printf("Enter first term:");
scanf("%lf", &first_d);
printf("Enter second term:");
scanf("%lf", &second_d);
sum_d = first_d + second_d;
printf("The sum is: %lf\n", sum_d);
break;
case 2:
printf("Enter first term:");
scanf("%lf", &first_d);
printf("Enter second term:");
scanf("%lf", &second_d);
difference_d = first_d - second_d;
printf("the difference is: %lf\n", difference_d);
break;
case 3:
printf("Enter first term:");
scanf("%lf", &first_d);
printf("Enter second term:");
scanf("%lf", &second_d);
product_d = first_d * second_d;
printf("The product is: %lf\n", product_d);
break;
case 4:
printf("Enter first term:");
scanf("%lf", &first_d);
printf("Enter second term:");
scanf("%lf", &second_d);
quotient_d = first_d/ (double)second_d;
printf("The quotient is: %lf\n", quotient_d);
if(second_d == 0){
printf("Cannot divide by 0!\n");
} else {
printf("Calculator now works with single precision.\n");
}
break;
}
}
case 6:
return 0;
default:
printf(" 1 - addition\n 2 - subtraction\n 3 - multiplication\n 4 - division\n");
printf(" 5 - toggle precision\n 6 - exit program\n");
break;
}
}
}

Answer 1

As the comments on your original post have said, you simply forgot a break.
After your fifth case, a break would cause the code to leave the switch statement and continue looping input. Because you forgot this break, the code finished in the fifth case and continued into the sixth case. The sixth case then exits, which is what your output was originally.
Add a break statement at the end of the fifth case, and you should be all set to go.