Add character array to const string& in C++

Question

char stringToAdd[4097] = ""; 

// some manipulations on stringToAdd to add some value to it. 

if(stringToAdd[0] != '\0') { 
response = MethodCalledHere("Some Random text");
}

MethodCalledHere(const String& inputParameter) {
 // some method definition here.
}

I've to add stringToAdd to the "Some Random text". Something like -

response = MethodCalledHere("Some Random text" + stringToAdd);

But this gives me error that '+' cannot add two pointers.

Any suggestions?

You can use `std::stringstream`, or encapsulate the first string in a constructor... — Charles, Sep 12 '17 at 19:06
The C++14 cool cats use `""s + "Some Random text" + stringToAdd;` Note the built in user defined literal. Unlike the + abomination in Java, this is not a kludge. — Bathsheba, Sep 12 '17 at 19:09
@Bathsheba - This seems like fixing the error but I didn't get the concept. If you can explain a bit. — user2769790, Sep 12 '17 at 19:11

R Sahu · Answer 1 · 2017-09-12T19:15:13.850

2

But this gives me error that '+' cannot add two pointers.

That's because in that context, both sides of the + operator are pointers.

Use

response = MethodCalledHere(std::string("Some Random text") + stringToAdd);

If your function expects char const*, then, you can construct a std::string first and then use std:string::c_str().

std::string s = std::string("Some Random text") + stringToAdd;
response = MethodCalledHere(s.c_str());

If you are able to use C++14, you can use the string literal (Thanks are due to @Bathsheba for the suggestion).

response = MethodCalledHere("Some Random text"s + stringToAdd);

edited Sep 12 '17 at 19:15

answered Sep 12 '17 at 19:08

R Sahu

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This is closed so I can't answer, but feel free to wack in the C++14 way: see my question comment. Nice answer though as it is, have an upvote. – Bathsheba Sep 12 '17 at 19:11
1

@Bathsheba, thanks for the suggestion. Hope the modified expression is still valid. – R Sahu Sep 12 '17 at 19:16
it's better than the way I had it. – Bathsheba Sep 13 '17 at 06:56

score 0 · Answer 2 · answered Sep 12 '17 at 19:07

0

auto MethodCalledHere(std::string inputParameter) {
    inputParameter.append(stringToAdd, 
                          stringToAdd + std::strlen(stringToAdd));
    return inputParameter;
}

answered Sep 12 '17 at 19:07

Richard Hodges

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Add character array to const string& in C++

2 Answers2