Question

I was working out this exercise and wanted to know if my answer is correct;

Write a program to print a histogram of the frequencies of different
characters in the input.

I have seen a couple of other answers online but they differ quite a lot to mine. Also if there are any problems in the format of my code or any improvements to be made. Any suggestions are welcome. I do understad the question requires a histogram but it’s quite easy to build one once I have the data required.

#include <stdio.h>
int main(){

    int userInput;
    int arrayStuff[92];
    int i, j;

    for(i = 0; i < 92; ++i){
        arrayStuff[i] = 0;
    }

    while((userInput = getchar()) != '\n'){
        if(userInput >= 30 && userInput <= 122){
            if(userInput != '\n'){
                ++arrayStuff[(userInput-30)];
            }

            if(userInput == '\n'){
                break;
            }
        }
    }

    printf("Case\t|\tOccurances\n");

    for(i = 0; i < 92; ++i){
        printf("%c\t|\t%d\n", (i+30), arrayStuff[i]);
    }
}

Answer 1

Improvements I’d make:

• Declare and initialize int arrayStuff[92] = { 0 }; in one go and get rid of the for loop. This is guaranteed to set all elements to 0.
• Don’t use the magic number 92 in various places, use (sizeof arrayStuff/sizeof arrayStuff[0]) instead to compute the number of elements in arrayStuff.
• Parentheses in (i+30) are redundant
• What happens if the user types the EOF character? It looks like it loops forever.
• “Occurances” is not in my dictionary, but occurrence is. Maybe character frequency is a better term?
• arrayStuff? I cannot overemphasize the importance of clear and concise identifier naming. Frequency comes to mind.
• It must be int main (void) with a return 0;. This is not C++, where an empty parameter list is equivalent to void. This is C, where an empty parameter list means “I’m an old-style K&R parameter list for an unknown but fixed number of arguments.”