C++ string swap character places

Question

is there a way to swap character places in a string? For example if I have "03/02" I need to get "02/03". Any help is appreciated!

https://msmvps.com/blogs/jon_skeet/archive/2010/08/29/writing-the-perfect-question.aspx — FailedDev, Nov 19 '11 at 17:58
If your question is deeper than the two answers, then you need to expand on it to tell us what you're really asking? — Mordachai, Nov 19 '11 at 18:00

score 41 · Accepted Answer · answered Nov 19 '11 at 17:58

41

Sure:

#include <string>
#include <algorithm>

std::string s = "03/02";
std::swap(s[1], s[4]);

answered Nov 19 '11 at 17:58

Kerrek SB

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@KerrekSB I don't think you'd benefit from move semantics in this case? – Mahmoud Al-Qudsi Nov 19 '11 at 18:22
Why would using move on the arguments be more general? – Benjamin Lindley Nov 19 '11 at 18:37
@BenjaminLindley: You're right, the interna of swap are unaffected. Let me remove those comments then. Perhaps an rvalue overload could let you swap with a temporary, but that's not relevant to this situation. Cheers. – Kerrek SB Nov 19 '11 at 22:24

score 4 · Answer 2 · answered Nov 19 '11 at 17:58

4

std::swap(str[1], str[4]);

answered Nov 19 '11 at 17:58

Oliver Charlesworth

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score 4 · Answer 3 · answered Nov 19 '11 at 17:59

4

There is. :)

std::swap(str[i], str[j])

answered Nov 19 '11 at 17:59

Paul Manta

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score 0 · Answer 4 · answered Nov 19 '11 at 18:12

Wait, do you really want such a specific answer? You don't care about if the string is 2/3 instead of 02/03?

#include <string.h>
#include <iostream>

bool ReverseString(const char *input)
{
    const char *index = strchr(input, (int) '/');
    if(index == NULL)
        return false;

    char *result = new char[strlen(input) + 1];

    strcpy(result, index + 1);
    strcat(result, "/");
    strncat(result, input, index - input);

    printf("%s\r\n", result);
    delete [] result;

    return true;
}

int main(int argc, char **argv)
{
    const char *test = "03/02";
    ReverseString(test);
}

but it did answer my question and now I know how to solve the whole exercise :D — RnD, Nov 19 '11 at 18:13

C++ string swap character places

4 Answers4

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