How to get rid of the following Error...

pl_kode

This is what I am doing... string str="MAX"; switch(str) { case "A":{ func1();} case "B":{ func2();} case "C":{ func3();} } following is the error I get.. error C2450: switch expression of type 'class std::basic_string,class std::allocator >' is illegal No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called Please help me resolve this... THANKS.

ahmad_ali

You cannot switch on a string because the string is not an integral type. Integral means "simple" types such as int, long, short, char, ... You can achieve the same behavior using if ... else if if(str=="A") { } else if(str=="B") { } ...

toxcct

have you heard of the if keyword ? a switch can work only with integers, not strings...

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Rajesh R Subramanian

toxcct wrote:

a switch can work only with integers,

Integral type, rather. :)

Nobody can give you wiser advice than yourself. - Cicero .·´¯`·->Rajesh<-·´¯`·. Codeproject.com: Visual C++ MVP

Madan Chauhan

hi, you should use integer or char instead of string in switch. like:: int a; switch(a) { case 1:{fun1(); break;} }

toxcct

indeed, but i didn't want to complexify my answer, as the OP doesn't seem to know C++, so i doubt he actually knows that a char is a small int !!! ;)

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CPallini

if your string is actually composed by a single character then the switch construct is viable, for instance:

string str="B";
switch( str[0])
{
case 'A':
{
//...
}
break;
case 'B':
{
//...
}
break;
case 'C':
{
//...
}
break;
default:
{//no matching
//...
}
break;
}

On the other hand, if you need to actually compare strings (i.e. more than 1 character involved) then you have to use a chain of if statements, for instance:

string str = "foo";
if ( str == "first option")
{
//...
}
else if (str == "second option")
{
//...
}
else if (str == "foo")
{
//...
}
else
{//no matching
//...
}

:)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke