Calculating the % of comment text in a file - c

Question

I'm trying to calculate the percentage of comment text in a file but I can't figure out what's wrong with my calculation method.
#include <stdio.h>
#include<stdlib.h>
int main()
{
int k, commNum1 = 0, commNum2 = 0, Nbrackets1 = 0, Nbrackets2 = 0, Cbrackets1 = 0, Cbrackets2 = 0, tabs = 0, spaces = 0;
char str[10000];
char ch, file_name[75];
FILE *fp;
char writtenText[2000];
printf("Enter the name of file you wish to see with extension .c or .txt\n");
gets(file_name);
fp = fopen(file_name, "a"); // reads the file
if (fp == NULL)
{
perror("Error while opening the file.\n");
_getche();
exit(EXIT_FAILURE);
}
printf("Enter a sentence:\n");
gets(writtenText);
fprintf(fp, "%s", writtenText);
fclose(fp);
fp = fopen(file_name, "r");
printf("The contents of %s file are :\n\n", file_name);
int i = 0;
while ((ch = fgetc(fp)) != EOF) {
// printf("%c", ch);
str[i] = ch; //printing and storing process
i++;
}
int fsize = i;
for (k = 0; k < fsize; k++) {
if (str[k] == '(')
Nbrackets1++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == ')')
Nbrackets2++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == '{')
Cbrackets1++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == '}')
Cbrackets2++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == '\t')
tabs++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == ' ')
spaces++;
}
for (k = 0; k < fsize; k++) {
if (str[k] == '/' && str[k + 1] == '*') {
while (str[k] != '*' && str[k + 1] != '/') {
commNum1++;
if (str[k] == ' ') {
commNum1--;
}
// printf("commNum1 = %d\n",commNum1); //just to test if my calculations are correct
k++;
}
}
}
for (k = 0; k < fsize; k++) {
if (str[k] == '/' && str[k + 1] == '/') {
while (str[k] != '\n') {
commNum2++;
if (str[k] == ' ') {
commNum2--;
}
// printf("commNum2 = %d\n",commNum2); //just to test if my calculations are correct
k++;
}
}
}
double commAVG = (commNum1 + commNum2) / fsize * 100;
double avgTAS = (tabs + spaces) / 2;
printf("\n\nOccurence of character ( : %d", Nbrackets1);
printf("\nOccurence of character ) : %d", Nbrackets2);
printf("\nOccurence of character { : %d ", Cbrackets1);
printf("\nOccurence of character } : %d ", Cbrackets2);
printf("\nAverage number of spaces and tabulations: %2.f", avgTAS);
printf("\nPercentage of comment text in the file: %2.f%%", commAVG);
fclose(fp);
return 0;
}
My view is that the for loop goes through the whole array in which the text is stored. If it meets a specific set of characters (/* or //) it starts adding 1 to an int. While adding if it finds spaces in between, it subtracts 1. If it meets another specific character or set of characters (/* or \n) it stops adding and the for loop takes over and finishes searching through the whole array. The problem is that it's calculating something else and I can't figure out the flaw in my method. Thanks !

Answer 1

Lets do a little play through... (the thing you should do with your debugger)
for (k = 0; k < fsize; k++) {
if (str[k] == '/' && str[k + 1] == '*') {
while (str[k] != '*' && str[k + 1] != '/') {
commNum1++;
if (str[k] == ' ') {
commNum1--;
}
// printf("commNum1 = %d\n",commNum1); //just to test if my calculations are correct
k++;
}
}
}
Consider the text "/* abc */"
if (str[0] == '/' && str[1] == '*') // true
while (str[0] != '*' && str[1] != '/') // true
commNum1++;
k++;
while (str[1] != '*' && str[2] != '/') // false, cause str[1] == '*'
End of story.
You should try to first increment k above the comment start and then change the while condition
while (str[k] != '*' || str[k + 1] != '/') // instead of &&
Also, in loops where you use look-ahead, adjust your bounds
for (k = 0; k < (fsize - 1); k++) // instead of k < fsize
Maybe you have more errors, but this is the obvious one.
Edit:
Since you mentioned the 400% problem:
You potentially add the same comment for both, commNum1 and commNum2, if the comment is formed like //* comment text or /*// comment text */
Also, your inner while loops don't check for k < fsize, which means that the check will reach beyond the end of array for the last line in file. There you get undefined behavior, potentially counting after-end-of-file-comments until 400% are reached.
Things I'm not going to address further:
/\
* comment starts here, cause \ is preprocessor line removal which merges the two lines into a /*