Do while loop calculator only works once in C

Question

I made this do while loop calculator program in C for our school activity, but it only work once. I expect it to work every time the user inputs 1 in the prompt.

When I run the code, the program works as expected. It functions as calculator but when I try to put the number "1" in the prompt at the end, it will loop but in the "Do you want to continue part only.
Here is the code:

#include <stdio.h>


int main() {
    
    
    int again;
    double num1, num2;
    const double PI = 3.1415; 
    char op;
    do {
        printf("Enter '+' to use addition.\n");
        printf("Enter '-' to use subtraction.\n");
        printf("Enter '*' to use multiplication.\n");
        printf("Enter '/' to use division.\n");
        printf("Enter 'c' to calculate the circumference of a circle.\n");
        printf("Enter 'a' to calculate the area of a circle.\n");
        printf("Enter what operation to do: ");
        scanf("%c", &op);

        switch(op) {
            case '+':
                printf("Enter a number: ");
                scanf("%lf", &num1);
                printf("Enter another number: ");
                scanf("%lf", &num2);
                printf("The answer is: %lf", num1 + num2);
                break;
            case '-':
                printf("Enter a number: ");
                scanf("%lf", &num1);
                printf("Enter another number: ");
                scanf("%lf", &num2);
                printf("The answer is: %lf", num1 - num2);
                break;
            case '*':
                printf("Enter a number: ");
                scanf("%lf", &num1);
                printf("Enter another number: ");
                scanf("%lf", &num2);
                printf("The answer is: %lf", num1 * num2);
                break;
            case '/':
                printf("Enter a number: ");
                scanf("%lf", &num1);
                printf("Enter another number: ");
                scanf("%lf", &num2);
                printf("The answer is: %lf", num1 / num2);
                break;
            case 'c':
                printf("Enter radius: ");
                scanf("%lf", &num1);
                printf("The answer is: %lf", 2 * PI * num1);
                break;
            case 'a':
                printf("Enter radius: ");
                scanf("%lf", &num1);
                
                printf("The answer is: %lf", PI * num1 * num1);
                break;
            
        }
        printf("\nDo you want to continue? Type '1' to continue and '2' to stop. \n");
        scanf("%d", &again);
    }while(again == 1);
    return 0;
}

Sorry if I can't explain the problem well, English is not my native language so please bear with me.

Do while loop calculator only works once in C

0 Answers0