C/C++ Find Min/Max Miles in milesTracker Program

[ineedhelpnow]

ok so i haven't looked at my programming homework in almost two weeks so I am very confused on how to do this.

Find the maximum value and minimum value in milesTracker. Assign the maximum value to maxMiles, and the minimum value to minMiles. Sample output for the given program:

Min miles: -10
Max miles: 40
Sample program:

#include <iostream>
using namespace std;

int main( ) {
   const int NUM_ROWS = 2;
   const int NUM_COLS = 2;
   int milesTracker[NUM_ROWS][NUM_COLS];
   int i = 0;
   int j = 0;
   int maxMiles = -99; // Assign 0 before loop
   int minMiles = -99; // Assign 0 before loop

   milesTracker[0][0] = -10; 
   milesTracker[0][1] = 20; 
   milesTracker[1][0] = 30; 
   milesTracker[1][1] = 40;

   <STUDENT CODE>

    cout << "Min miles: " << minMiles << endl;
    cout << "Max miles: " << maxMiles << endl;
}

help please :(

 

[MarkFL]

You are going to want to loop through the array...since you know the dimensions of the array, what kind of looping construct do you think is appropriate?

 

[ineedhelpnow]

for?

 

[MarkFL]

for?

Correct! (Nod)

Now, since you have two dimensions in the array, you are going to need a for loop nested within another for loop. The outer loop will loop through the rows, and the inner loop will loop through the columns. Can you set up the loops, using the provided indices and dimensions?

 

[ineedhelpnow]

Correct! (Nod)

Now, since you have two dimensions in the array, you are going to need a for loop nested within another for loop. The outer loop will loop through the rows, and the inner loop will loop through the columns. Can you set up the loops, using the provided indices and dimensions?

for(i=0;i<NUM_ROWS;++i) is the first loop
for(j=0;i<NUM_COLS;++j) is the second loop

i think that's wrong but I am not sure.

 

[MarkFL]

for(i=0;i<NUM_ROWS;++i) is the first loop
for(j=0;i<NUM_COLS;++j) is the second loop

i think that's wrong but I am not sure.

That's correct...I would set them up as follows:

for (i = 0; i < NUM_ROWS; i++)
{
    for (j = 0; i < NUM_COLS; j++)
    {
        //code goes here
    }
}

Now, we are going to be doing some comparisons, but on the very first value, we have no previous values to compare, so...what do you think we should do on the very first iteration of the loops? In other words:

for (i = 0; i < NUM_ROWS; i++)
{
    for (j = 0; i < NUM_COLS; j++)
    {
        if (i == 0 && j == 0)
        {
            //first iteration
        }
        else
        {
            //all other iterations
        }
    }
}

 

[ineedhelpnow]

im not sure

 

[MarkFL]

im not sure

Well, what I would do is assign the first value to both the max and min values:

for (i = 0; i < NUM_ROWS; i++)
{
    for (j = 0; i < NUM_COLS; j++)
    {
        if (i == 0 && j == 0)
        {
            minMiles = milesTracker[i][j];
            maxMiles = milesTracker[i][j];
        }
        else
        {
            //all other iterations
        }
    }
}

Now, for all other iterations...what conditions will cause you to change the values of minMiles and maxmiles?

 

[ineedhelpnow]

i was trying this the whole time.

for(i=0;i<NUM_ROWS;++i){
      for(j=0;i<NUM_COLS;++j){
             if (milesTracker[i][j]<minMiles){
                   minMiles = milesTracker[i][j];
            }
             else if (milesTracker[i][j] > maxMiles){
                   maxMiles = milesTracker[i][j];
            }
   } 
}

- - - Updated - - -

i got it to work. the way i was doing it, i just forgot to initialize them to 0 before starting the loop.

thanks.

 

[MarkFL]

i was trying this the whole time.

for(i=0;i<NUM_ROWS;++i){
      for(j=0;i<NUM_COLS;++j){
             if (milesTracker[i][j]<minMiles){
                   minMiles = milesTracker[i][j];
            }
             else if (milesTracker[i][j] > maxMiles){
                   maxMiles = milesTracker[i][j];
            }
   } 
}

Okay good...I would suggest putting your if/else construct where I have "all other iterations." What you have would work with the values you are given for the array, but it would fail in general. Consider the case where you initialize the min and max values to some value, but then all of the values in the array are greater than that initial value (or all of them are smaller)...your min/max values would never get changed. :D

 

[MarkFL]

...i got it to work. the way i was doing it, i just forgot to initialize them to 0 before starting the loop.

thanks.

Yes, but a good coder tries to make his/her code work as generally as possible. ;)

 

[ineedhelpnow]

Yes, but a good coder tries to make his/her code work as generally as possible. ;)

:) i posted that before your last post. i agree with you

 

[EvanET]

i was trying this the whole time.

for(i=0;i<NUM_ROWS;++i){
      for(j=0;i<NUM_COLS;++j){
             if (milesTracker[i][j]<minMiles){
                   minMiles = milesTracker[i][j];
            }
             else if (milesTracker[i][j] > maxMiles){
                   maxMiles = milesTracker[i][j];
            }
   } 
}

- - - Updated - - -

i got it to work. the way i was doing it, i just forgot to initialize them to 0 before starting the loop.

thanks.

on your second for statement make this correction:

for(j=0;j<NUM_COLS;++j)

this is what it said before:

for(j=0;i<NUM_COLS;++j)

all i changed was the i and made it j, this completed the code and ran everything.