make a calculator in c or write a code calculator

 #include<stdio.h>

#include<conio.h>

int main(void)

{

float a,b;

char sign;

printf("Press 'q' to quit\n");

printf("Enter any number :");

scanf("%f",&a);

do{

printf("Enter any operator :");

scanf("%s",&sign);

printf("Enter any number :");

scanf("%f",&b);

switch(sign){

case'+':

a=a+b;

printf("Result :%.2Lf\n",a);

break;

case'-':

a=a-b;

printf("Result :%.2f\n",a);

break;

case'*':

a=a*b;

printf("Result :%.2f\n",a);

break;

case'/':

a=a/b;

printf("Result :%.2f\n",a);

break;

case'%':

a=(b*a)/100;

printf("Result :%.2f\n",a);

break;

default:

printf("Invalid Operator\n");

}

}

while(sign!='q');

printf("Thank you\n");

getch();

}