c program for frequency of occurences

[oormilarev]

dear all
i want and as fast as possible a working C program for the following problem.
i have an array values[ ] consisting of 'n' float values say ranging from 0 - 18. i want to get the frequencies of the values in class intervals of 0 - 1.99, 2 - 3.99, 4 - 5.99 etc. My attempts do not give me the proper results. especially for the first class interval 0 - 1.99. HELP !!!


My program

#include<stdio.h>
#define maxrl 10
#define bins 10
 
main()
{
  FILE *fp1,*fp2;
    float value[maxrl];
    int i;
    int group[bins];
 
    for(i=0;i<bins;i++)
    group[bins] = 0;
    fp1 = fopen("RL.dat","r");
    fp2 = fopen("RL_freq.dat","w");
for(i=0;i<maxrl;i++){
  fscanf(fp1,"%f",&value[i]);
  ++group[(int)(value[i]/2)];
 
}
fprintf(fp2,"\n");
fprintf(fp2,"no. of bins\tbins\t frequency\n");
 
for(i=0;i<bins;i++)  {
 
    fprintf(fp2,"%d\t\t %2d\t\t%d \n",i+1,2*i,group[i]);
}
fclose(fp1);
fclose(fp2);
}

[sicarie]

Please use code tags around your code, they help greatly with readability.

Ok, you have a few issues here - you have a for loop with no { } statement, an undefined variable (bins), and it doesn't look like you have started the part where you count the ranges. If this is for a class assignment, I would recommend sitting down with your teacher for a few hours - there's some fundamental stuff here that needs to be fixed, and you need help with the algorithm/logic of the program.

[Dana Good]

dear all
i want and as fast as possible a working C program for the following problem.
i have an array values[ ] consisting of 'n' float values say ranging from 0 - 18. i want to get the frequencies of the values in class intervals of 0 - 1.99, 2 - 3.99, 4 - 5.99 etc. My attempts do not give me the proper results. especially for the first class interval 0 - 1.99. HELP !!!


My program

#include<stdio.h>
#define maxrl 10
#define bins 10
 
main()
{
  FILE *fp1,*fp2;
    float value[maxrl];
    int i;
    int group[bins];
 
    for(i=0;i<bins;i++)
    group[bins] = 0;
    fp1 = fopen("RL.dat","r");
    fp2 = fopen("RL_freq.dat","w");
for(i=0;i<maxrl;i++){
  fscanf(fp1,"%f",&value[i]);
  ++group[(int)(value[i]/2)];
 
}
fprintf(fp2,"\n");
fprintf(fp2,"no. of bins\tbins\t frequency\n");
 
for(i=0;i<bins;i++)  {
 
    fprintf(fp2,"%d\t\t %2d\t\t%d \n",i+1,2*i,group[i]);
}
fclose(fp1);
fclose(fp2);
}

Among other things, you're not zeroing your group bins because you're not using 'i' in your 'for' loop. So your numbers will be completely wacky.

You really should also check the returns from your fopens, etc... and be very careful with floats generally.