Rolling Dice Histogram - c

Question

Hello I have written the code needed for a dice rolling generator base on rand() and time.h.
It basically asks the user to input the number of times he wants the dice to be rolled and then rolls those X times. It saves the times each one of 1-6 number was rolled in an array and the percentage of each number in another array.
Now what I want to do is create a histogram the has the numbers 1-6 and - on the X-axis, the percentages and | on the Y-axis and stars(*) for columns.
Something like this:
10% | *
8% |* * *
6% |* * * * *
4% |* * * * * *
2% |* * * * * *
+------------
1 2 3 4 5 6
I have search throught google to find something to begin with but I have really found anything similar to my case thats gonna help me begin with.
My code thus for is:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int random_number();
float calc_percentage(int totals, int nums);
float calc_maxper(float perc[6]);
float calc_minper(float perc[6]);
float permin;
float permax;
int main(void)
{
int nums;
int i;
int totals[6] = {0};
float percentages[6] = {0};
srand(time(NULL));
printf("How many numbers to generate?");
scanf("%d", &nums);
for (i = 1; i <= nums; i++)
{
int x = random_number();
totals[x-1]++;
}
for (i = 0; i<6; i++)
{
percentages[i] = calc_percentage(totals[i],nums);
printf("The percentage of each number is: %.2f%\n", percentages[i]);
}
permin = calc_minper(percentages);
permax = calc_maxper(percentages);
if (((permax) - (permin)) > 5)
printf("The generator is not good.\n");
printf("The percentage difference is:%.1f\n", permax-permin);
system("pause");
return 0;
}
int random_number()
{
int randnum;
randnum = 1 + (rand() % 6);
return randnum;
}
float calc_percentage(int totals, int numbers)
{
float a;
a = (totals * 100)/numbers;
return a;
}
float calc_minper(float perc[6])
{
int i;
float min;
min = perc[0];
for (i=1; i<6; i++)
{
if (perc[i] < min)
min = perc[i];
}
return min;
}
float calc_maxper(float perc[6])
{
int i;
float max;
max = perc[0];
for (i=1; i<6; i++)
{
if (perc[i] > max)
max = perc[i];
}
return max;
}
Ok I finally got this done.
Kinda long and messy but it definitely gets the job done!!
printf("20%|");
for (i=0; i<6; i++)
{
if (percentages[i] >= 20)
printf("* ");
}
printf("\n");
printf("16%|");
for (i=0; i<6; i++)
{
if (percentages[i] >= 16)
printf("* ");
}
printf("\n");
printf("12%|");
for (i=0; i<6; i++)
{
if (percentages[i] >= 12)
printf("* ");
}
printf("\n");
printf(" 8%|");
for (i=0; i<6; i++)
{
if (percentages[i] >= 8)
printf("* ");
}
printf("\n");
printf(" 4%|");
for (i=0; i<6; i++)
{
if (percentages[i] >= 4)
printf("* ");
}
printf("\n");
printf(" +------------\n");
printf(" 1 2 3 4 5 6\n");
Thanks dude for your ideas!!
If u have any quick ideas to make it shorter am all ears!

Answer 1

For each range (10%, 8%, etc), check if the current dice number (1-6) percentage exceeds it, then print a * (or a space if it doesn't meet the range minimum). At the end, print the graph base.
You could use a for to handle the ranges:
float range;
float interval = (permax-permin)/(NUM_INTERVALS-1);
for (range = permax; range >= permin - EPSILON; range -= interval){
int i;
printf("%2.2f%% | ", range);
for(i=0; i<6; i++){
char *out = percentages[i] >= range ? "*" : " ";
printf("%s ", out);
}
printf("\n");
}
printf(" | 1 2 3 4 5 6\n");