Case bypasses initialization of a local variable

[Edy1Q]

#include <iostream.h>
#include <conio.h>
int main()
{
int a;
cout<< "ingrese un numero entre 1 y 4 gracias\n";
cin>> a;
switch(a)
{
case 1:
cout<< "este es el comienzo de c++ \n";
break;

case 2:
cout<< "Tabla de Multiplicar\n";
int num=0;
int res=0;

cout<< "ingrese un numero\n";
cin>> num;

for (int i=1; i<=10; i++)
{
res=num*i;
cout<< num<< "*" <<i<< "=" <<res<< "\n";
}
break;

case 3:
for(int e=1; e<=1000; e++)
{
cout<<"Ya Casi Terminas El Programa \n";
}
break;

case 4:
int n=1;
cout<< "Ingrese La Nota De Un Alumno\n";
if(n>=60 && n<=100)
{
cout<< "Gano El Curso\n";
}
else
{
if(n>=0 && n<=59)
{
cout<< "Perdio El Curso\n";
}
else
{
cout<< "Nota No Valida\n";
}
break;
}
}
getch ();
return 0;
}

[weaknessforcats]

cin >> a

does not guarantee that the variable is initialized. It will be initialized only if the cin stream is not in error.

Just set the variable to 0 when you define it.