scientific or simple calculator

statement: write a code in which user first select what type calculator they want to use. Simple or scientific and on that basis they do the calculations.
I have written the following code but it is not running. I am unable to figure out the problem. Please anybody help!!

#include <iostream>
#include <string.h>
#include <conio.h>
#include <math.h>
using namespace std;
int main()
{
int input;
cout << "CHOOSE BETWEEN SCIENTIFIC AND SIMPLE CALCULATOR:" << endl;
cout << "[1] Scientific" << endl << "[2] Simple" <<endl;
cin >> input;

switch(input) 
case '1':
float a,b;
int z;
void Power(float,float);
void Sine(float);
void Square(float);
void Cos(float);
void Tan(float);
void Log(float);
void Baselog(float);
cout<<"WHAT YOU WANT TO FIND: "<<endl;
cout<<"Press '1' for Power: "<<endl;
cout<<"Press '2' for Sin: "<<endl; 
cout<<"Press '3' for Square: "<<endl; 
cout<<"Press '4' for Cos: "<<endl; 
cout<<"Press '5' for Tan: "<<endl;
cout<<"Press '6' for Log: "<<endl;
cout<<"Press '7' for Base Log: "<<endl;

cin>>z;
switch(z)
{
case 1:
cout<<"Enter the Number for Calculating its Power: "<<endl;
int a;
cin>>a;
cout<<"Enter the Power for a Number: "<<endl;
int b;
cin>>b;
Power(a,b);
break;

case 2:
cout<<"Enter the Number for Calculating SIN: "<<endl;
cin>>a;
Sine(a);
break;

case 3:
cout<<"Enter the Number for Calculating Square: "<<endl;
cin>>a;
Square(a);
break;

case 4:
cout<<"Enter the Number for Calculating COS: "<<endl;
cin>>a;
Cos(a);
break;

case 5:
cout<<"Enter the Number for Calculating TAN: "<<endl;
cin>>a;
Tan(a);
break;

case 6:
cout<<"Enter the Number for Calculating LOG: "<<endl;
cin>>a;
Log(a);
break;

case 7:
cout<<"Enter the Number for Calculating LOG WITH BASE 10: "<<endl;
cin>>a;
Baselog(a);
break;
}
getch();
}

void Power(float x,float y)
{
float p;
p = pow(x,y);
cout<<"Power: "<<p;
}

void Sine(float x)
{
float s;
s = sin(x);
cout<<"Sin: "<<s;
}

void Square(float x)
{
float sq;
sq = sqrt(x);
cout<<"Square of a Given Value is: "<<sq;
}

void Cos(float x) 
{
float c;
c = cos(x);
cout<<"COS: "<<c;
}

void Tan(float x)
{
float t;
t = tan(x);
cout<<"TAN: "<<t;
}

void Log(float x)
{
float l;
l = log(x);
cout<<"Natural Logarithm: "<<l;
}

void Baselog(float x);

float bl;
bl = log10(x);
cout<<"LOG with Base 10: "<<bl;

break;

case '2':

int num1,num2;
char op;
cout << "Enter an operator (+, -, *, /): ";
cin >> op; 
cout << "Enter two numbers: " << endl;
cin >> num1 >> num2;

if(op=='+') {
    cout << num1 << " + " << num2 << " = " << num1 + num2; }

else if(op=='-') {
    cout << num1 << " - " << num2 << " = " << num1 - num2; }

else if(op=='*') {
    cout << num1 << " * " << num2 << " = " << num1 * num2; }

else if(op=='/') {
    cout << num1 << " / " << num2 << " = " << num1 / num2; }

else{
        cout << "Error! The operator is not correct"; 
    }            
break;  

return 0;
}