Question

#C++

Write a function, named sortByCourseNumber, that takes a reference to a vector of string (like {"CSE 232", "ECE 100", "CSE 450", "CSE 232"}) and returns nothing. The function should reorder the vector so that the courses are sorted by number in ascending order. You can assume that the department code is separated from the number by a space and that all course numbers are 3 characters long.

You should be using the STL algorithms to achieve this, full credit is only possible if your solution doesn't have any looping constructs (no "while" or "for" keywords anywhere in the solution). If a URL you are citing has such a word, add an interupting space like: https://www.programiz.com/cpp-programming/fo r-loop

Answer 1

I have used for loop just for displaying the vector. It has nothing to do with sorting the vector.

Here is the code for your problem.

#include <bits/stdc++.h>

using namespace std;

// compare function for sorting

bool compare(string s1, string s2)

{

    // these 2 variables store last 3 digits of the string

    // it is mentioned in the question that the length of code is 3

    stringstream num1(s1.substr(s1.length() - 3));

    stringstream num2(s2.substr(s2.length() - 3));

    // converting string to integer

    int code1, code2;

    num1 >> code1;

    num2 >> code2;

    // returning true if code1 is less than or equal to code2

    return (code1 <= code2);

}

// main function

int main()

{

    // initializing vector

    // this is just for testing purpose

    vector<string> course = {"CSE 232", "ECE 100", "CSE 450", "CSE 232"};

    // this is the sort method call using compare function

    sort(course.begin(), course.end(), compare);

    // I have used for loop just for displaying

    // it has nothing to do with sorting

    for (string i : course)

    {

        cout << i << endl;

    }

    return 0;

}

Here is the screenshot of the code if the indentation is not clear.

Here is the output of the code.

Hope this helps.

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