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

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", &numone);

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

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", &numtwo);
                             ^

Your if-else statement needs to be fixed.

else {
numtwo = 0;
}

StackExchange Code Review Q#68695, answer score: 3