Thread: Bar graph troubles

Thank you for the suggestions. I can't really explain, so here is the example I'm supposed to be emulating:

Code:

45
40
35
30        *****
25        ***** *****
20        ***** *****
15        ***** *****
10  ***** ***** *****
5   ***** ***** *****
0   ***** ***** *****
    -----------------------------------
    00-05 05-10 10-15 15-20 20-25 25-30

I know how I can go through and check each part of the array if there should be a print out there, but I can't figure out how I can align it properly with the bottom.

Also, is there any way I can improve how I'm printing out the bottom? I feel like my way of doing it is...lazy.

You need to print out what units are being represented by the numbers we're seeing here. These numbers mean nothing, as is.

The bottom row is lazy, but that's good. Looks could be improved a bit, but that's a last detail.

Get a sample of the data posted up, so we can talk about specifics. Doesn't need to be your project's data, just similar data.

Ok, here's a link to what I have so far and the sample txt I'm reading from: http://dl.dropbox.com/u/10771960/fuelgraph.zip

Originally Posted by Adak

Some questions for you:

1) Why are you dividing min by 5 in the program?

2) how is time to be represented in the bar graph? Are those to be 5 second intervals, on the bottom of the graph, with mpg on the far left side?

3) Why are you dividing distance traveled, by 63360? The equation I'm familiar with is:
mpg = distance/gas consumed

4) Have you confirmed that your math for this, is correct?

5) Why 301?

Code:

for(i=1;i != 301;i++) {
  //etc.
}

1) Dividing by five because the graph presents information in intervals of five. Dividing by five gives me how many times I need to check the .txt file.

2) The bottom of the graph is five minute intervals.

3) Can't remember off the top of my head but that equation involves tire radius and revolutions. It's more than just distance and gas used.

4) Yes my math is correct.

5) The .txt file stores information about a car per second. Because I need information in five minute intervals, I need to add up 300 seconds worth of information.

Everything works as necessary except for the actual printing of the graph bit.

Your program only provides 3 numbers into the mpg array. (min = 3).

This is the output given the following mpg array numbers:

Code:

 10.033465
 32.441399
 28.829947

 45|                               
 40|                               
 35|                               
 30|       *****                   
 25|       ***** *****             
 20|       ***** *****             
 15|       ***** *****             
 10| ***** ***** *****             
  5| ***** ***** *****             
  0| ***** ***** *****             
     -----------------------------------
     00-05 05-10 10-15 15-20 20-25 25-30
Press any key to continue . . .

and this is the tweaked version that did that:

Code:

#include<stdio.h>

#define PI 3.14159
#define MIN 300
#define ROWS 10
#define COLS 30


void printGraph(double milesPG[], int min) {
    int i,j,r,c,n; 
    double num=0.0;
    char dat[ROWS][COLS]; 

    for(i=0;i<ROWS;i++) {   //set all dat elements to spaces
      for(j=0;j<COLS;j++)
        dat[i][j]=' ';
    }
    /* data[][] assignment block */
    printf("\n\n\n");
    for(i=0,c=0;i<min;i++) {  
      printf("\n %lf", milesPG[i]);
      num=milesPG[i]/5;        //to match vertical graduations
      for(j=0;j<num;j++) {
        dat[j][c]='*';
        dat[j][c+1]='*';
        dat[j][c+2]='*';
        dat[j][c+3]='*';
        dat[j][c+4]='*';
      }
      c+=6;
    }

  //print out block
  printf("\n\n");
  for(r=ROWS-1,n=45;r>-1;r--) {
    printf(" %2d| ", n);
    for(c=0;c<COLS;c++) {
      printf("%c",dat[r][c]);
    }
    putchar('\n');
    n-=5;
  }
  printf("     -----------------------------------\n");
  printf("     00-05 05-10 10-15 15-20 20-25 25-30\n");

}

int main(){
    
    int min, inches, c=0, i, flength;
    double totalRev=0, totalGas=0, rev, gas;
    char file[20];
    FILE *fp;
    double mpg[MIN];

    printf("\n\n\n");
    printf("What file stores the car data?\n");
    scanf("%s", &file); printf("\n");

    /* for IDE debug only
    strcpy(file, "fuelmpg.txt");    //for debug in IDE only
    flength = strlen(file);
    if(file[flength-1]=='\n')       // ditto
      file[flength-1]='\0';
    */

    fp = fopen(file, "r");
    if(fp==NULL) {
      printf("\nError opening %s\n", file);
      return 1;
    }
    fscanf(fp, "%d", &min);
    fscanf(fp, "%d", &inches);
    
    min = min/5;
    while(c<=(min-1)){
                for(i=1;i!=301;i++){
                        fscanf(fp, "%lf%lf", &rev, &gas);
                        totalRev+=rev, totalGas+=gas;
                        }
                mpg[c] = ( PI * inches * 2 * totalRev / 63360 ) / totalGas;
                c++;
                totalRev=0, totalGas=0;
                }
    
  printGraph(mpg, min);
  fclose(fp);
  (void) getchar();
  system("PAUSE");
  return 0;
}

Thank you for your help! Using your advice I thought up how to get what I needed. Here's how I did it:

Code:

void printGraph( double milesPG[], int min ){ //gets passed mpg array and array length; prints graph
     int y=100, c, x;
     while(y!=0){y-=5; printf("%-4d", y); //prints left side
     
         for(c=0;c<=(min-1);c++){ //runs through the array
            for(x=0;x<5;x++){ //decides whether to print star or spaces
               if(milesPG[c]>=y)
                 putchar('*');
               else
                 putchar(' ');}
                 
         putchar(' ');}
                 
         putchar('\n');}
             
                 
     printf("    -----------------------------------\n");
     printf("    00-05 05-10 10-15 15-20 20-25 25-30\n");
}

Using y to test the value is smart - well done!