Not getting output for division and modulus - c

Question

The below C program gives me output only for Addition(+), difference(-), multiplication(*).
But when I try to use division(/) and modulus(%) the program just close itself without giving any error. Help me I'm a newbie to C programming.
//A simple calculator.
#include<stdio.h>
#include<conio.h>
void main()
{
int a, b, sum, diff, rem, multi;
float div;
char character;
clrscr();
printf("Choose the character you want to use(+, -, *, /, %): ");
scanf("%c", &character);
switch(character)
{
case '+': //will be used for addition.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
sum = a+b;
printf("The sum of the %d and %d is %d", a, b, sum);
break;
case '-': //will be used for difference.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
diff = a-b;
printf("The difference between %d and %d is %d", a, b, diff);
break;
case '%': //will be used for modulus.
printf("Enter the first and second number: ");
scanf("%f %f", &a, &b);
rem = a%b;
printf("The remainder of %f and %f is %f", a, b, rem);
break;
case '*': //will be used for product of 2 no.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
multi = a*b;
printf("The multiplication of %d and %d is %d", a, b, multi);
break;
case '/': //will be used for the division.
printf("Enter the first and second number: ");
scanf("%f %f", &a, &b);
div = a/b;
printf("The division of %f and %f is %f", a, b, div);
break;
default:
printf("Error! character please retry");
}
getch();
}

Answer 1

You are using %f format specifier for int variables in / and % cases.
scanf("%f %f", &a, &b);
Thus invoking undefined behavior.
Change it to as below.
scanf("%d %d", &a, &b);
%f is used to readin the float variables.
If you want float result for division, you need to cast the one of the argument to float instead reading them as float.
div = (float)a/b;

Answer 2

When using the / and % use
scanf("%d %d", &a, &b);
instead of
scanf("%f %f", &a, &b);
because %f is used for float vars whereas in case of / and % %d is used

Answer 3

You are using wrong formats. After enabling -Wall in gcc and fixing the warnings I get a working program. You also missing the \n in your answer printf()'s
#include <stdio.h>
int main(int argc, char **argv)
{
int a, b, sum, diff, rem, multi;
float div;
char character;
printf("Choose the character you want to use(+, -, *, /, %%): ");
scanf("%c", &character);
switch(character)
{
case '+': //will be used for addition.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
sum = a+b;
printf("The sum of the %d and %d is %d\n", a, b, sum);
break;
case '-': //will be used for difference.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
diff = a-b;
printf("The difference between %d and %d is %d\n", a, b, diff);
break;
case '%': //will be used for modulus.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
rem = a%b;
printf("The remainder of %d and %d is %d\n", a, b, rem);
break;
case '*': //will be used for product of 2 no.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
multi = a*b;
printf("The multiplication of %d and %d is %d\n", a, b, multi);
break;
case '/': //will be used for the division.
printf("Enter the first and second number: ");
scanf("%d %d", &a, &b);
div = a/b;
printf("The division of %d and %d is %f\n", a, b, div);
break;
default:
printf("Error! character please retry");
}
}
Test output:
$ ./dummy
Choose the character you want to use(+, -, *, /, %): %
Enter the first and second number: 5 2
The remainder of 5 and 2 is 1
$