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how to convert variable string into cons char
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I have to open a file named "axb.txt"
I have user input a and b as strings
i have concatenated the string using string str = a + "x" + b+ ".txt"
now i need to open the file.
it does not open with fopen(str, ios::app)
because str is not a const char pointer.
what to do?
I have user input a and b as strings
i have concatenated the string using string str = a + "x" + b+ ".txt"
now i need to open the file.
it does not open with fopen(str, ios::app)
because str is not a const char pointer.
what to do?
change str to
The function c_str() converts your std::string to a
I personally like
str.c_str() The function c_str() converts your std::string to a
const char * which is what the constructor of fopen wants. I personally like
std::ofstream(str.c_str()) better for opening files. One thing I noticed was that you did
To answer, your question, yeah just use
string str = a + "x" + b+ ".txt" It should be string str = "a" + "x" + "b" + ".txt" because if you just put a and b without quotes, the compiler will think that you are using the variables a and b.To answer, your question, yeah just use
str.c_str() like niek_e said. 
>...because if you just put a and b without quotes, the compiler will think that you are using the variables a and b.
That's exactly what OP intends to do
That's exactly what OP intends to do
Oh, yeah... Just was confused from when he wrote "axb.txt"
Nevermind, the first part of my previous post
Nevermind, the first part of my previous post
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