Structure and readability of basic calculator I created this code to make a basic calculator after viewing a few examples. I added the function to continue the calculations myself. I am wondering if there is a way to make this more efficient as I feel I've used some unnecessary code but I can't make it work without.

I also was looking for feedback on my codes readability and how to improve if it is of a poor quality.

#include &lt;stdio.h&gt;

int main ()
{
int cancel = 1;
char o, end  = 'Y';
float numone = 0.0, numtwo = 0.0;

         /* Explaining structure and receiving inputs */

         printf("Please enter the two numbers you wish to manipulate!\n");
         scanf("%f", &amp;numone);

         do {
                 scanf("%f", &amp;numtwo);
                 printf("Please enter the operation you wish to perform (+, -, *, /)\n");
                 scanf(" %c", &amp;o);

                 /* Checking for correct input and manipulating numbers with regards to user input */

                 switch(o){

                         case '+':
                                 printf("%.1f + %.1f = %.1f\n", numone, numtwo, numone + numtwo);
                                 break;
                         case '-':
                                 printf("%.1f - %.1f = %.1f\n", numone, numtwo, numone - numtwo);
                                 break;
                         case '*':
                                 printf("%.1f * %.1f = %.1f\n", numone, numtwo, numone * numtwo);
                                 break;
                         case '/':
                                 printf("%.1f / %.1f = %.1f\n", numone, numtwo, numone / numtwo);
                                 break;
                         default:
                                 /* Error message for incorrect input */
                                 printf("Error! Incorrect input!\n");
                                 break;
                 }`enter code here`
                 /* Option to continue calculations */

                 printf("Would you like to perform a further calculation? (Y/N)\n");

                 /* Checking for answer and terminating if N, resuming if Y */

                 scanf(" %c%", &amp;end);
                        if (end == 'N') {
                         return 0;
                        }
                        else {}
                 numtwo = 0;

                 /* Requesting new number to use as numtwo for calculations */

                 printf("Current number = %f please input a second number!\n", numone);
                 } while (end == 'Y');

         return 0;
}
Minor stuff:

I'm getting several compiler warnings. Capture the returned variable
    from scanf() to check if the user actually entered a number. 

main.cpp:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%f", &amp;numtwo);
                             ^


Your if-else statement needs to be fixed.

else {
numtwo = 0;
}