C program to design a CALCULATOR

#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
int choice,d,c,r;
float a,b,total;
clrscr();
printf("\t\t\t\tcalculator");
printf("\n\t\t\t\t----------");
printf("\n enter 1 for addition");
printf("\n enter 2 for subtraction");
printf("\n enter 3 for multiplication");
printf("\n enter 4 for division");
printf("\n enter 5 for modulus");
printf("\n enter 6 for square");
printf("\n enter 7 for square root");
printf("\n\n enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1:
printf("\n enter 1st no : ");
scanf("%f",&a);
printf("\n enter 2nd no : ");
scanf("%f",&b);
total=a+b;
printf("\nyour %f + %f=%f",a,b,total);
break;

case 2:
printf("\n enter 1st no : ");
scanf("%f",&a);
printf("\n enter 2nd no : ");
scanf("%f",&b);
total=a-b;
printf("\nyour %f - %f=%f",a,b,total);
break;

case 3:
printf("\n enter 1st no : ");
scanf("%f",&a);
printf("\n enter 2nd no : ");
scanf("%f",&b);
total=a*b;
printf("\nyour %f * %f=%f",a,b,total);
break;

case 4:
printf("\n enter 1st no : ");
scanf("%f",&a);
printf("\n enter 2nd no : ");
scanf("%f",&b);
total=a/b;
printf("\n your %f / %f=%f",a,b,total);
break;

case 5:
printf("\n enter 1st no : ");
scanf("%d",&c);
printf("\n enter 2nd no : ");
scanf("%d",&d);
r=c%d;
printf("\n your %d  %%  %d = %d",c,d,r);
break;

case 6:
printf("\n enter any no : ");
scanf("%f",&a);
total=a*a;
printf("\n your %f * %f =%f",a,a,total);
break;

case 7:
printf("\n enter any no : ");
scanf("%f",&a);
total=sqrt(a);
printf("\n required square root of your no. =%f",total);
break;

default:
printf("error");
break;
}
getch();
}