Reducing my list of if loops

[jmastin]

To put it bluntly I need help. The large number of variables is the only way that I can get the function to work. I don't know how to reduce them to the point where it will be decent size and work the same way. I have tried everything I know and it doesn't work except for all the if loops.

#include<iostream>
#include<iomanip>
#include<cmath>

using namespace std;

const int MONTHS = 12;//Constant for number of months.
void getMonth(string months[], int& month);// Asks user for current month.
void getAvg(double avgRain[],string months[], int& i);
void getAct(double actRain[],string months[], int& j, int& month);
void printTable(double avgRain[], double actRain[],string months[], double& totalAvg, double& totalAct, double& sum3, double& sum4, double& sum5, double& sum6, double& sum7, double& sum8, double& sum9, double& sum10, double& sum11, double& sum12, double& sum13, double& sum14, double& sum15, double& sum16, double& sum17, double& sum18, double& sum19, double& sum20, double& sum21, double& sum22, double& sum23, double& sum24, double& sum25, double& sum26);
const int ZERO = 0;
const int WIDTH1 = 20;
const int WIDTH2 = 20;
const int WIDTH3 = 8;

int main()
{

     double avgRain[MONTHS];
     double actRain[MONTHS];
     double totalAvg,totalAct,sum3,sum4,sum5,sum6,sum7,sum8,sum9,sum10,sum11,sum12,sum13,sum14,sum15,sum16,sum17,sum18,sum19,sum20,sum21,sum22,sum23,sum24,sum25,sum26;
     int i,j, month;
     string months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

     getAvg(avgRain,months,i);
     getMonth(months, month);//Calls getMonth function.
     getAct(actRain,months,j,month);
     totals(avgRain,actRain,months,i,j,totalAvg,totalAct,sum3,sum4,sum5,sum6,sum7,sum8,sum9,sum10,sum11,sum12,sum13,sum14,sum15,sum16,sum17,sum18,sum19,sum20,sum21,sum22,sum23,sum24,sum25,sum26);
     

    return 0;
}
 
     
void getMonth(string months[],int& month)// Asks user for current month.
{

     cout << "\nPlease enter the current month. "
          << "Use 1 for January, 2 for February, "
          << "and so on." << endl;
     cin  >> month;
     
    if (month > ZERO && month <= MONTHS)
	{
		cout << "\nThe current month is " << months[month - 1] << endl;
	}
	else
	{
		cout << "You must enter a number between 1 and 12." << endl;
		getMonth(months, month);
	}
    return;
}

void getAvg(double avgRain[],string months[], int& i)
{
     int month = 1;

     cout << "\nPlease enter the average rainfall for each month" << endl;
     for (int i = ZERO; i < MONTHS; i++)
     {
	cout << months[i]<<" : ";
	cin  >> avgRain[i];
     }
     return;
}
void getAct(double actRain[],string months[], int& j, int& month)
{
     
 
     cout << "\nPlease enter the actual monthly rainfall for the previous 12 months. Begin with the current month: "<< months[month - 1] << endl;
     
     for (j = (12 - 1); j >= 0; --j)

     {
         cout << months[j] << " : ";
         cin  >> actRain[j];
     }
     return;
}

void totals(double avgRain[], double actRain[],string months[], int& i, int& j, double& totalAvg, double& totalAct, double& sum3, double& sum4, double& sum5, double& sum6, double& sum7, double& sum8, double& sum9, double& sum10, double& sum11, double& sum12, double& sum13, double& sum14, double& sum15, double& sum16, double& sum17, double& sum18, double& sum19, double& sum20, double& sum21, double& sum22, double& sum23, double& sum24, double& sum25, double& sum26)
{
     double sum = 0, sum2 = 0;
     

     if ( *avgRain > *actRain )
     {
          sum3 = *avgRain - *actRain;
          sum4 = ZERO;
          if ( sum3 == ZERO && sum4 == ZERO )
          {
               sum3 = ZERO;
               sum4 = ZERO;
          }
     }     
     if ( *(avgRain + 1) > *(actRain + 1) )
     {     
          sum5 = *(avgRain + 1) - *(actRain + 1);
          sum6 = ZERO;
     }
     if ( *(avgRain + 2) > *(actRain + 2) )
     {
          sum7 = *(avgRain + 2) - *(actRain + 2);
          sum8 = ZERO;
     }
     if ( *(avgRain + 3) > *(actRain + 3) )
     {
          sum9 = *(avgRain + 3) - *(actRain + 3);
          sum10 = ZERO;
     }
     if ( *(avgRain + 4) > *(actRain + 4) )
     {
          sum11 = *(avgRain + 4) - *(actRain + 4);
          sum12 = ZERO;
     }
     if ( *(avgRain + 5) > *(actRain + 5) )
     {
          sum13 = *(avgRain + 5) - *(actRain + 5);
          sum14 = ZERO;
     }
     if ( *(avgRain + 6) > *(actRain + 6 ))
     {
          sum15 = *(avgRain + 6) - *(actRain + 6);
          sum16 = ZERO;
     }
     if ( *(avgRain + 7) > *(actRain + 7) )
     {
          sum17 = *(avgRain + 7) - *(actRain + 7);
          sum18 = ZERO;
     }
     if ( *(avgRain + 8) > *(actRain + 8) )
     {
          sum19 = *(avgRain + 8) - *(actRain + 8);
          sum20 = ZERO;
     }
     if ( *(avgRain + 9) > *(actRain + 9) )
     {
          sum21 = *(avgRain + 9) - *(actRain + 9);
          sum22 = ZERO;
     }
     if ( *(avgRain + 10) > *(actRain + 10) )
     {     
          sum23 = *(avgRain + 10) - *(actRain + 10);
          sum24 = ZERO;
     }
     if ( *(avgRain + 11) > *(actRain + 11) )
     {         
          sum25 = *(avgRain + 11) - *(actRain + 11);
          sum26 = ZERO;
     }
     if ( *actRain > *avgRain )
     {
          sum4 = *actRain - *avgRain;
          sum3 = ZERO;
     }
     if ( *(actRain + 1) > *(avgRain + 1) )
     {          
          sum6 = *(actRain + 1) - *(avgRain + 1);
          sum5 = ZERO;
     }
     if ( *(actRain + 2) > *(avgRain + 2) )
     {          
          sum8 = *(actRain + 2) - *(avgRain + 2);
          sum7 = ZERO;
      }
     if ( *(actRain + 3) > *(avgRain + 3) )
     {         
          sum10 = *(actRain + 3) - *(avgRain + 3);
          sum9 = ZERO;
     }
     if ( *(actRain + 4) > *(avgRain + 4) )
     {          
          sum12 = *(actRain + 4) - *(avgRain + 4);
          sum11 = ZERO;
     }
     if ( *(actRain + 5) > *(avgRain + 5) )
     {         
          sum14 = *(actRain + 5) - *(avgRain + 5);
          sum13 = ZERO;
     }
     if ( *(actRain + 6) > *(avgRain + 6) )
     {         
          sum16 = *(actRain + 6) - *(avgRain + 6);
          sum15 = ZERO;
     }
     if ( *(actRain + 7) > *(avgRain + 7) )
     {          
          sum18 = *(actRain + 7) - *(avgRain + 7);
          sum17 = ZERO;
     }
     if ( *(actRain + 8) > *(avgRain + 8) )
     {          
          sum20 = *(actRain + 8) - *(avgRain + 8);
          sum19 = ZERO;
     }
     if ( *(actRain + 9) > *(avgRain + 9) )
     {          
          sum22 = *(actRain + 9) - *(avgRain + 9);
          sum21 = ZERO;
     }
     if ( *(actRain + 10) > *(avgRain + 10) )
     {         
          sum24 = *(actRain + 10) - *(avgRain + 10);
          sum23 = ZERO;
     }
     if ( *(actRain + 11) > *(avgRain + 11) )
     {         
          sum26 = *(actRain + 11) - *(avgRain + 11);
          sum25 = ZERO;
     }
     

         
     sum = sum + *avgRain + *(avgRain + 1) + *(avgRain + 2) + *(avgRain + 3) + *(avgRain + 4) + *(avgRain + 5) + *(avgRain + 6) + *(avgRain + 7) + *(avgRain + 8) + *(avgRain + 9) + *(avgRain + 10) + *(avgRain + 11);
     //cout << sum << " is the test" << endl;
     totalAvg = sum;
     //cout << totalAvg << " is the test" << endl;
     sum2 = sum2 + *actRain + *(actRain + 1) + *(actRain + 2) + *(actRain + 3) + *(actRain + 4) + *(actRain + 5) + *(actRain + 6) + *(actRain + 7) + *(actRain + 8) + *(actRain + 9) + *(actRain + 10) + *(actRain + 11);
     //cout << sum2 << " is the test" << endl;
     totalAct = sum2;
     //cout << totalAct << " is the test" << endl;

     return;     
}

[Galik]

If loops? I never heard that term before ;o)

Your ifs arn't looking very loopy to me, perhaps you need a for loop?

double total(double avgRain[])
{
    double total = 0.0; // accumulator

    for(int i = 0; i < size, ++i) // loop where i takes on values from 0 to size - 1
    {
        total = total + avgRain[i]; // use [i] rather than *(avgRain + i) because its neater
    }

    return total;
}

[Disch]

You need to learn about arrays.

// very bad

void func(int& v1,int& v2,int& v3,int& v4)
{
  v1 = 1;
  v2 = 2;
  v3 = 3;
  v4 = 4;
}

int main()
{
  int v1, v2, v3, v4;
  func(v1,v2,v3,v4);
}

//better

void func(int* v)
{
  for(int i = 0; i < 4; ++i)
    v[i] = i+1;
}

int main()
{
  int v[4];
  func(v);
}

As a general rule of thumb... if you find yourself naming things "sum1, sum2, sum3" etc, you're doing things wrong.

Also if you're copy/pasting blocks of code and only changing variables names, you're doing something wrong.


EDIT:

I also thought this was comical:

const int ZERO = 0;

is 'ZERO' really any more clear than '0'?