CODEWITHSUNDEEP
c++decltype
grady s.
grady s.

Reputation: 13

decltype was not declared in this scope

I am trying to make a program that reads strings and tells me how many punctuation marks are in it. However, when I try to compile it, it gives the error, "'decltype' was not declared in this scope'. I have just started c++ in the last month and am new to its concepts.

I'm using Dev C++ 5.11 as the IDE for the code. The code is from the book c++ Primer fifth edition on page 92

#include<iostream>
#include<cctype>
#include<string>

using namespace std;

int main() {
    string s("Hello World!!!");
    decltype(s.size() punct_cnt = 0;

    // count the number of punctuation characters in s
    for (auto c : s) // for every char in s
        if (ispunct(c)) // if the character is punctuation
            ++punct_cnt;
    cout << punct_cnt << " punctuation characters in " << s << endl;
}

I expect it to give the output 3, but it gives the error message, "'decltype' was not declared in this scope'.

Upvotes: 0

Views: 812

Answers (1)

nanofarad
nanofarad

Reputation: 41271

decltype was only introduced in C++11, and presumably DevC++ is not instructing the compiler to use c++11 mode. In your compiler options, instruct DevC++ to pass the following command-line flag:

-std=c++11

Upvotes: 3

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