CODEWITHSUNDEEP
c++switch-statement
Prajogo Atmaja
Prajogo Atmaja

Reputation: 37

New to C/C++ Language. What has gotten wrong?

and thank you for viewing this post. I need some help for my programming. I used to compile with turbo pascal and now I'm learning C++. Here's the problem.
I want to make a mathematics thing with an input and output something like this.
Input(in pseudocode):

Var a,b:=int; op:=char;
readln(a);
readln(b);
case op of
"+" : write(a+b);
"-" : write(a-b);
">" : if a>b then write("true"); else write("false");

I've tried to do it in C++ like this but it failed to be compiled. I don't put include here because i don't really understand why is it become bold. I wrote it something like this.

void main()
{
    int a,b,c;
    char op;
    std::cin>>a>>op>>b;
    switch (c){
    case (std::cin>>op == "+") :{
        c=a+b;
        std::cout<<c<<std::endl;
                           }
    }
}

this is the error

1>test03.cpp(10): error C2051: case expression not constant

1>test03.cpp(14): warning C4060: switch statement contains no 'case' or 'default' labels
can anyone help me? thanks.

Upvotes: 0

Views: 189

Answers (2)

John Sheridan
John Sheridan

Reputation: 446

You are not too far off the mark. The compiler is telling you exactly what the problem is. You must use a constant in your case expression.

You have a few other problems in there too and you have no error handling.

But to help you get started, try this ...

void main()
{
    int a, b, c;
    char op;

    std::cin >> a >> op >> b;

    switch(op){
    case '+':
        c = a + b;
        break;
    }

    std::cout << c << std::endl;
}

Upvotes: 1

user1300630
user1300630

Reputation:

You don't assign any value to c, it contains garbage when you want to use it in the switch block.

I think You wanted to write 

switch(op)

and 

case '+'

Upvotes: 3

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