I am creating a simple CLI calculator tool as an exercise. The complete code is included below. I need to make sure n1 and n2 are numeric in order for the functions to work; somewhat consequently, I would like to make the program quit upon coming across a non-numeric value from the user.
Can anyone give me some direction?
Check out the first if statement in the do block. (its commented out)
Thank you!
Can anyone give me some direction?
Check out the first if statement in the do block. (its commented out)
Thank you!
Code:
#include <iostream>
#include <new>
using namespace std;
double factorial(double n) { return (n <= 1) ? 1 : n * factorial(n - 1); }
double add(double n1, double n2) { return(n1 + n2); }
double subtract(double n1, double n2) { return(n1 - n2); }
double multiply(double n1, double n2) { return(n1 * n2); }
double divide(double n1, double n2) { return(n1 / n2); }
int modulo(int n1, int n2) { return(n1 % n2); }
double power(double n1, double n2) {
double n = n1;
for(int i = 1 ; i < n2 ; i++) {
n *= n1;
}
return(n);
}
void print_problem(double n1, double n2, char operatr) {
cout<<n1<<operatr<<flush;
if(operatr != '!') {
cout<<n2<<flush;
}
cout<<"="<<flush;
}
int main(void) {
double* n1, * n2, * result = NULL;
char* operatr = NULL;
n1 = new (nothrow) double;
n2 = new (nothrow) double;
result = new (nothrow) double;
operatr = new (nothrow) char;
if(n1 == NULL || n2 == NULL || operatr == NULL || result == NULL) {
cerr<<"\nMemory allocation failure.\n"<<endl;
} else {
do {
cout<<"calculator>> "<<flush;
cin>>*n1;
// if(*n1 is not numeric) {
// break;
// }
cin>>*operatr;
if(*operatr == '!') {
print_problem(*n1, *n2, *operatr);
cout<<factorial(*n1)<<endl;
} else {
cin>>*n2;
switch(*operatr) {
case '+':
print_problem(*n1, *n2, *operatr);
cout<<add(*n1, *n2)<<endl;
break;
case '-':
print_problem(*n1, *n2, *operatr);
cout<<subtract(*n1, *n2)<<endl;
break;
case '*':
print_problem(*n1, *n2, *operatr);
cout<<multiply(*n1, *n2)<<endl;
break;
case '/':
if(*n2 > 0) {
print_problem(*n1, *n2, *operatr);
cout<<divide(*n1, *n2)<<endl;
} else {
print_problem(*n1, *n2, *operatr);
cout<<" cannot be computed."<<endl;
}
break;
case '%':
if(*n1 >= 0 && *n2 >= 1) {
print_problem(*n1, *n2, *operatr);
cout<<modulo(*n1, *n2)<<endl;
} else {
print_problem(*n1, *n2, *operatr);
cout<<" cannot be computed."<<endl;
}
break;
case '^':
print_problem(*n1, *n2, *operatr);
cout<<power(*n1, *n2)<<endl;
break;
default:
cout<<"Invalid Operator"<<endl;
}
}
} while(true);
delete n1, n2, operatr, result;
}
return(0);
}