I tried to write a program that can help me find trigonometric values of a given angle. Below is the program,

```
    #include<iostream>
#include<cmath>
using namespace std;

void convert(char type);

int main()
{
    char ch;

    cout<<"Enter what angle value u want to calculate: 'c' for cos, 's' for sine and 't' for tan: ",cin>>ch;

    convert(ch);

    return 0;
}

void convert(char type)
{
    float angle;
    double num;
    switch (type)
    {
        case 'C' || 'c':
            cout<<"Enter angle value to calculate cos equivalent: ",cin>>angle;
            num = cos(angle);
            break;
        case 's' || 'S':
            cout<<"Enter angle value to calculate sin equivalent: ",cin>>angle;
            num = sin(angle);
            break;
        case 'T' || 't':
            cout<<"Enter angle value to calculate tan equivalent: ",cin>>angle;
            num = tan(angle);
            break;
        default:
            cout<<"\n\nInvalid Character\n";
    }
}

```

But the code gives me error as 

> 
> [Error] duplicate case value
> 
> 
> 

Someone please help me understand the logic behind this error and an alternate solution for this problem.

Regards,