Vectored Pairs: unclear on bits of concept

[OldFangle]

Hi

I'm self-testing to see what I understand of C++ thus far, in particular Vectors and Pairs.
(I'm trying to incorporate the use of a Vector comprised of Pairs)

Scenario:
A JOB BOARD displays available deliveries. Between 1 and 5 categories are listed.
Within a FOR loop, the programme determines in each case whether to display that category.

Each Category is assigned a PAIR containing a string variable and an INT variable.
e.g. "Greenhouse",100
I'm hopefully then correctly building--and later properly accessing--the PAIRs in that Vector.

Within the FOR loop I attempt to use rand() to determine first whether to list each of the five choices.
If the item is chosen for display I then attempt to update the PAIR item's INT value by multiplying it with a number determined by a separate rand() call.

Here's the code:

#include <iostream>
#include <string>
#include <vector>
#include <time.h> // for random number generator, but I'm not using it in this Sample
#include <utility>  // for pair
#include <math.h>

using namespace std;    // I'm not using most of this but I'm keeping the code clean for now; I can add std::  later

// Declaring VARIABLES
int firstChoice;
int ifListed;
int jobsPay;
int jobsProfit;
int i;
// END Declaring VARIABLES


int main() {

// JOB BOARD
	cout << "************************************************************************" << endl;
	cout << "************************** JOB BOARD ******************************" << endl;
	cout << "************************************************************************\n\n";


// First declare pairs, then make vector of those pairs

pair<string, int> delivery1 ("Clothiers",100);
delivery1.first = "Clothiers";					// are these two lines
delivery1.second = 100;						// necessary?
delivery1 = make_pair(string("Clothiers"), 100);

pair<string, int> delivery2;
delivery2.first = "Greenhouse";
delivery2.second = 200;
delivery2 = make_pair(string("Greenhouse"), 200);

pair<string, int> delivery3;
delivery3.first = "Factory";
delivery3.second = 300;
delivery3 = make_pair(string("Factory"), 300);

pair<string, int> delivery4;
delivery4.first = "Workshop";
delivery4.second = 400;
delivery4 = make_pair(string("Workshop"), 400);

pair<string, int> delivery5;
delivery5.first = "Smithy";
delivery5.second = 500;
delivery5 = make_pair(string("Smithy"), 500);

//Now make vector of these pairs

vector< pair<string, int> > deliveryJobs;
deliveryJobs.push_back(delivery1);        // Should these specify pair's STRING and INT?  If so, what's the syntax?
deliveryJobs.push_back(delivery2);
deliveryJobs.push_back(delivery3);
deliveryJobs.push_back(delivery4);
deliveryJobs.push_back(delivery5);

// This attempts to determine whether to display each of the five categories, and also attempts to multiply the Pair's INT with a random number

	cout << "These Delivery Jobs are available...\n\n";
	for (i = 0; i < deliveryJobs.size(); ++i) {    		// hopefully incrementing *after* the FOR loop runs
		int ifListed = rand() % 2;					// trying to get a 0 or 1 to use in an IF statement 
		if (ifListed != 0) {
				jobsProfit = (rand() % 3) + 3;             // trying to create a random set of numbers 3 through 5
				deliveryJobs[i].second = jobsPay;     // trying to call, through the vector, the INT from PAIR Delivery[i].second
				jobsPay = (jobsPay + jobsProfit);   
				}
		
		cout << i+1 << ") " << deliveryJobs[i].first << " : " << jobsPay << endl;
		}

	return 0;
}

>>> RESULT WHEN PROGRAMME RUNS:

These Delivery Jobs are available...

1) Clothiers : 4
2) Greenhouse : 9
3) Factory : 9
4) Workshop : 9
5) Smithy : 9

<<< END

...and it's always the same read-out. I'm hoping to get some of these categories randomly omitted. I'm also trying to access the Pairs' INTs e.g. 100, 200, and multiply those by a random number 3 through 5.

I've toyed with various options for several hours and it's been lots of fun but I've been staring at it too long.
I might be overlooking the declaration of certain variables, or declaring variables incompletely...
I probably have one or two lines of code in the wrong place *and* slightly out-of-whack, so I'm not managing to consider all the options when I re-try code.


Thanks in advance for taking the time to point-out errors.