C Program to Implement Calculator using Functions

#include<stdio.h>
int n,a,b,res;


void addnum(int a,int b)
{
printf("%d",a+b);
}

void subnum(int x,int y)
{
printf("%d",x-y);
}

void mulnum(int a,int b)
{
int p;
p=a*b;
printf("%d",p);
}

void divnum(int a,int b)
{
printf("%d",a/b);
}

int main()
{
printf("Enter two Numbers for the Operation n");
scanf("%d%d",&a,&b);

printf("Enter n1.Additionn2.Subtractionn3.Multiplicationn4.Divisionn");
scanf("%d",&n);


switch (n)
{
case 1:
addnum(a,b);
break;

case 2:
subnum(a,b);

case 3:
mulnum(a,b);

case 4:
divnum(a,b);

}
return 0;
}