I would change the main section to this:
bool valid = true;
switch (oper)
{
case '+':
total = num1 + num2;
break;
case '-':
total = num1 - num2;
break;
case '*':
total = num1 * num2;
break;
case '/':
total = num1 / num2;
break;
default:
printf("Follow the directions next time!\n");
valid = false;
break;
}
if (valid)
{
printf("\n\n%.2f %c %.2f = %.2f\n", num1, oper, num2, total);
}
The general code, however, is pretty damn good.