std::basic_istream::peek - cppreference.com

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# std::basic_istream::peek

From cppreference.com
< cpp‎ | io‎ | basic istream

int_type peek(); |  |

Behaves as `UnformattedInputFunction`. After constructing and testing the sentry object, reads the next character from the input stream without extracting it.

### [edit] Parameters

(none)

### [edit] Return value

If good() == true, returns the next character as obtained by rdbuf()->sgetc()

Otherwise, returns Traits::eof().

### [edit] Exceptions

[edit]
failure if an error occurred (the error state flag is not goodbit) and exceptions() is set to throw for that state.

If an internal operation throws an exception, it is caught and badbit is set. If exceptions() is set for `badbit`, the exception is rethrown.

### [edit] Example

Run this code

    #include <sstream>
    #include <iostream>
    int main()
    {
        std::istringstream s1("Hello, world.");
        char c1 = s1.peek();
        char c2 = s1.get();
        std::cout << "Peeked: " << c1 << " got: " << c2 << '\n';
    }

Output:

    Peeked: H got: H

### [edit] See also

sgetc | reads one character from the input sequence without advancing the sequence (public member function of `std::basic_streambuf`) [edit]
get | extracts characters (public member function) [edit]
unget | unextracts a character (public member function) [edit]

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