It's still crashing, where am I going wrong? - c

Question

(Edited to add this bit) I'm writing a program where it reads in a string of characters, then counts the frequency of each letter in the string and outputs the number of times each letter or non-letter occurs.
I was using tolower() but this was creating a problem.
I've changed it so I'm now using a loop to lower the case. Unfortunately the program is still crashing on me and I can't spot the problem.
I've run through each function to make sure I don't have anything loose. I've got the new line element being removed but when I run it through, I type in something as simple as "hello" and it crashes out.
#include <stdio.h>
#include <string.h>
void read(char letterfreq[], int STRSIZE)
{
printf("The capacity of the string array is %d\n", STRSIZE-1);
printf("Please enter your string:\n");
letterfreq[strlen(letterfreq) - 1] = '\0';
return;
}
void lowerCase(char letterfreq[], int STRSIZE)
{
}
}
void countFreq(int counter[], int COUNT, char letterfreq[], int STRSIZE)
{
int c = 0;
int i;
for(i = 0; i < STRSIZE; i++)
}
else
if((letterfreq[i] < 'a') || (letterfreq[i] > 'z'))
{
counter[COUNT-1]++;
}
}
}
return;
}
void printFreq(int counter[], int COUNT)
{
int c;
printf("Here is the letter frequency of your string:\n");
for(c = 0; c < COUNT; c++)
printf("There were also %d special characters in the string.\n", counter[26]);
return;
}
char promptReset(char reset)
{
printf("Would you like to calculate the letter frequency of another string? (Y/N)\n");
scanf("%c%*c", &reset);
do
{
readString(letterfreq, STRSIZE);
lowerCase(letterfreq, STRSIZE);
countFreq(counter, COUNT, letterfreq, STRSIZE);
printFreq(counter, COUNT);
reset = promptReset(reset);
}while(reset == 'y' || 'Y');
return(0);
}

Answer 1

Here(in function lowerCase):
letterfreq[i] = letterfreq[i] - 32;
you need to add 32 to convert the character into uppercase. Look at the ASCII table to know why.
Here(in function countFreq):
for(i = 0; i < STRSIZE; i++)
{
while(letterfreq[i] != '\0')
{
if(letterfreq[i] >= 'a' && letterfreq[i] <= 'z')
{
counter[c]++;
c++;
}
else
if((letterfreq[i] < 'a') || (letterfreq[i] > 'z'))
{
counter[COUNT-1]++;
}
}
}
the for loop doesn't make any sense. Remove it. Then, the while loop never ends as you don't increment i. You need i++; at the end of the while loop.
Here:
if(letterfreq[i] >= 'a' && letterfreq[i] <= 'z')
{
counter[c]++;
c++;
}
counter[c]++ won't count the frequency of each character. You need
counter[letterfreq[i]-'a']++;
for that. c is not needed. Remove it from the function.
Also, as #iharob has mentioned in a comment,
}while(reset == 'y' || 'Y');
should be
}while(reset == 'y' || reset == 'Y');
Fixed program:
#include <stdio.h>
#include <string.h>
const int COUNT = 27;
const int STRSIZE = 100;
void readString(char letterfreq[], int STRSIZE)
{
printf("The capacity of the string array is %d\n", STRSIZE-1);
printf("Please enter your string:\n");
fgets(letterfreq, STRSIZE, stdin);
letterfreq[strlen(letterfreq) - 1] = '\0';
//return; Not required
}
void lowerCase(char letterfreq[], int STRSIZE)
{
int i;
for(i = 0; i < STRSIZE; i++)
{
if(letterfreq[i] >= 'A' && letterfreq[i] <= 'Z')
{
letterfreq[i] = letterfreq[i] + 32; //Add instead of subtract
}
//i++; You already increment i from the loop
}
}
void countFreq(int counter[], int COUNT, char letterfreq[], int STRSIZE)
{
int i=0; // You forgot to initialize i with 0
while(letterfreq[i] != '\0')
{
if(letterfreq[i] >= 'a' && letterfreq[i] <= 'z')
{
counter[letterfreq[i]-'a']++;
}
else if((letterfreq[i] < 'a') || (letterfreq[i] > 'z')) //is always true; Use `else`
{
counter[COUNT-1]++;
}
i++; //You forgot this
}
//return; Not required
}
void printFreq(int counter[], int COUNT)
{
int c;
printf("Here is the letter frequency of your string:\n");
for(c = 0; c < COUNT-1; c++) //See change here too
{
printf("%c \t %d \n", c + 'a', counter[c]);
}
printf("There were also %d special characters in the string.\n", counter[26]);
//return; Not required
}
char promptReset(char reset)
{
printf("Would you like to calculate the letter frequency of another string? (Y/N)\n");
scanf("%c%*c", &reset);
return(reset);
}
int main()
{
char letterfreq[STRSIZE];
char reset = '\0'; //Always initialize variables to prevent unexpected behavior
int counter[COUNT];
printf("Welcome to the Letter Frequency program\n");
do
{
memset(counter,0,sizeof(counter)); //Initializing counter with zeros
memset(letterfreq,'\0',sizeof(letterfreq)); //Do the same for letterfreq
readString(letterfreq, STRSIZE);
lowerCase(letterfreq, STRSIZE);
countFreq(counter, COUNT, letterfreq, STRSIZE);
printFreq(counter, COUNT);
reset = promptReset(reset);
}while(reset == 'y' || reset == 'Y'); //Changed
return(0);
}