strcmp help

[dunnpeaches]

ok I wrote the code I was to do and my teacher wants us to use a strcmp quit and my program was working great but if I add this function I get some errors. I'm not asking for anybody to do my home work I'm just needing some help.

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

using namespace std;

struct  Person {
	string name;
	int age;
	float salary;


};

int main(){



	Person record[10];
    int n;
    int i;
    n=i;
	for ( i = 0; i < 10; i++)
    {
        cout << "Enter  name: ";
		cin >> record[i].name;

		if( strncmp(record[i].name, "quit" ) == 0)

                   break;
		cout << " Enter salary: ";
		cin >> record[i].salary;
		cout << "\n";
    }

     n = i;
	for (i = 0; i < (10-1); i++)
	{
	    for ( n = (i +1); n < (10); n++)
        {
            if (record[i].salary < record[n].salary)
            {

                Person temp;
                temp=record[i];
                record[i]=record[n];
                record[n]=temp;
            }
        }
    }
        for (int i = 0; i < 10; i++)
	{
        cout << "Name: " << record[i].name;
		cout << "\nSalary: " << record[i].salary << endl << endl;
    }


	return 0;

}

**** the error code I keep getting is:
C:\Users\April\Documents\PROG02.cpp:28:38: error: cannot convert 'std::string {aka std::basic_string<char>}' to 'const char*' for argument '1' to 'int strncmp(const char*, const char*, size_t)'

[Zhuge]

strcmp() operates on C-style strings; if you really must use it instead of the standard string comparison operators, you will need to use the c_str() method.
http://www.cplusplus.com/reference/string/string/c_str/

[dunnpeaches]

ok so now I am really confused because my teacher why would my teacher tell me to do that when I'm in c++ I have no clue about c-style strings. he just wants us to use to quit the program before I added all that my program worked fine. So there no way I could use this for my program that I have now

[Chervil]

The simplest way to code that would be


if ( record[i].name == "quit" )

Perhaps your teacher got mixed up - sometimes if one is used to using several different coding languages, one may absent-mindedly drop something from one language into another where it really doesn't belong. I'd suggest maybe it was the intention, rather than the low-level detail which was important.

[dunnpeaches]

Ok i did what you said but now when i run my code its doing some crazy output.

[dhayden]

Is the idea to sort the number of records that you input? If that's true then you need to remember that number somewhere. If I run the program and give it 10 names and salaries it works for me:

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

using namespace std;

struct Person
{
    string name;
    int age;
    float salary;
};

int
main()
{

    Person record[10];
    int n;
    int i;

    for (i = 0; i < 10; i++) {
        cout << "Enter  name: ";
        cin >> record[i].name;

        if (record[i].name == "quit")
            break;
        cout << " Enter salary: ";
        cin >> record[i].salary;
        cout << "\n";
    }

    for (i = 0; i < (10 - 1); i++) {
        for (n = (i + 1); n < (10); n++) {
            if (record[i].salary < record[n].salary) {

                Person temp;
                temp = record[i];
                record[i] = record[n];
                record[n] = temp;
            }
        }
    }
    for (int i = 0; i < 10; i++) {
        cout << "Name: " << record[i].name;
        cout << "\nSalary: " << record[i].salary << endl << endl;
    }

    return 0;

}

[naaissus]

That's because you are printing all 10 elements of array but what if user entered data for e. g. 2 persons only? Same thing goes for sorting, you don't need (want) to sort all 10 elements if there are only 2 persons in array... You need to add some counter to count for how many persons you have data.
Also I think that there is no need for n = i; lines, especially for the first one because i is uninitialized at that moment.

[dunnpeaches]

How would i add a counter and the reson i have n=i is because that i was my instructor told me to do let me get to my computer so i can upload the code that i had before i put that quit function in

[dunnpeaches]

This is my code before I did what my teacher told me to do.

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

using namespace std;

struct  Person {
	string name;
	int age;
	float salary;
};

int main(){


	Person record[10];

	for (int i = 0; i < 10; i++)
	{
		cout << "Enter  name: ";
		cin >> record[i].name;
		cout << " Enter salary: ";
		cin >> record[i].salary;
		cout << "\n";

	}

	for (int i = 0; i < (10-1); i++)
	{
	    for (int j = (i +1); j < (10); j++)
        {
            if (record[i].salary < record[j].salary)

                {

                Person temp;
                temp=record[i];
                record[i]=record[j];
                record[j]=temp;
                }
            }
        }
      for (int i = 0; i < 10; i++)
	{
        cout << "Name: " << record[i].name;
		cout << "\nSalary: " << record[i].salary << endl << endl;


	}

	return 0;

}

[naaissus]

#include <iostream>
#include <string>

using namespace std;

struct  Person {
	string name;
	int age;
	float salary;
};

int main(){
	Person record[10];
    int n;
    int i;
    //n=i;

    int counter = 0;
    for (i = 0; i < 10; i++)
    {
        cout << "Enter  name: ";
	cin >> record[i].name;
	if(record[i].name == "quit")
            break;
	cout << " Enter salary: ";
	cin >> record[i].salary;
	cout << "\n";
        counter++;
    }
    //n = i;
    for (i = 0; i < counter - 1; i++)
    {
        for (n = (i + 1); n < counter; n++)
        {
            if (record[i].salary < record[n].salary)
            {
                Person temp;
                temp=record[i];
                record[i]=record[n];
                record[n]=temp;
            }
        }
    }
    for (int i = 0; i < counter; i++)
    {
        cout << "Name: " << record[i].name;
	cout << "\nSalary: " << record[i].salary << endl << endl;
    }
    return 0;
}

Btw you should avoid magic numbers (in bigger programs).
I. e. it's always better to write something like numOfElem - 1 than (10 - 1).
<string.h> (<cstring>) is header for C-strings and functions like strcmp, strcpy...
For C++ strings is <string>.

[dunnpeaches]

I understand the magic numbers thing I just wish I understood the strcmp better. My program now works thank yall so much!!! I really do appreciate all of yalls help!!