C beginner: Need explanation of error messages from "ideone" - c

Question

I am attempting to write a program that accepts grammatically incorrect text (under 990 characters in length) as input, corrects it, and then returns the corrected text as output. I attempted to run the program using the online compiler, "ideone", but it returned quite a few errors that I don't quite understand. I have posted my code, as well as a picture of the errors below. Can anybody explain to me what exactly the errors mean?
#include "stdio.h"
char capitalize(int i); //prototype for capitalize method
int main(void)
{
char userInput[1200]; //Array of chars to store user input. Initialized to 1200 to negate the possibility of added characters filling up the array.
int i; //Used as a counter for the for loop below.
int j; //Used as a counter for the second for loop within the first for loop below.
int numArrayElements;
printf("Enter your paragraphs: ");
scanf("%c", &userInput); //%c used since chars are expected as input(?)
numArrayElements = sizeof(userInput) / sizeof(userInput[0]); //stores the number of elements in the array into numArrayElements.
if (userInput[0] >= 97 && userInput[0] <= 122) //Checks the char in index 0 to see if its ascii value is equal to that of a lowercase letter. If it is, it is capitalized.
userInput[0] = capitalize(userInput[0]);
//code used to correct input should go here.
for (i = 1; i < numArrayElements; i++) //i is set to 1 here because index 0 is taken care of by the if statement above this loop
{
if (userInput[i] == 32) //checks to see if the char at index i has the ascii value of a space.
if (userInput[i + 1] == 32 && userInput[i - 1] != 46) //checks the char at index i + 1 to see if it has the ascii value of a space, as well as the char at index i - 1 to see if it is any char other than a period. The latter condition is there to prevent a period from being added if one is already present.
{
for (j = numArrayElements - 1; j > (i - 1); j--) //If the three conditions above are satisfied, all characters in the array at location i and onwards are shifted one index to the right. A period is then placed within index i.
userInput[j + 1] = userInput[j];
userInput[i] = 46; //places a period into index i.
numArrayElements++; //increments numArrayElements to reflect the addition of a period to the array.
if (userInput[i + 3] >= 97 && userInput[i + 3] <= 122) //additionally, the char at index i + 3 is examined to see if it is capitalized or not.
userInput[i + 3] = capitalize(userInput[i + 3]);
}
}
printf("%c\n", userInput); //%c used since chars are being displayed as output.
return 0;
}
char capitalize(char c)
{
return (c - 32); //subtracting 32 from a lowercase char should result in it gaining the ascii value of its capitalized form.
}

Answer 1

Your code hase several problems, quite typical for a beginner. Teh answer to teh question in your last commenst lies in the way scanf() works: it takes everything between whitepsaces as a token, so it just ends after hey. I commented the code for the rest of the problems I found without being too nitpicky. The comments below this post might do it if they fell so.
#include "stdlib.h"
#include "stdio.h"
#include <string.h>
// Check for ASCII (spot-checks only).
// It will not work for encodings that are very close to ASCII but do not earn the
// idiomatic cigar for it but will fail for e.g.: EBCDIC
// (No check for '9' because non-consecutive digits are forbidden by the C-standard)
#if ('0' != 0x30) || ('a' != 0x61) || ('z' != 0x7a) || ('A' != 0x41) || ('Z' != 0x5a)
#error "Non-ASCII input encoding found, please change code below accordingly."
#endif
#define ARRAY_LENGTH 1200
// please put comments on top, not everyone has a 4k monitor
//prototype for capitalize method
char capitalize(char i);
int main(void)
{
//Array of chars to store user input.
// Initialized to 1200 to negate the possibility of
// added characters filling up the array.
// added one for the trailing NUL
char userInput[ARRAY_LENGTH + 1];
// No need to comment counters, some things can be considered obvious
// as are ints called "i", "j", "k" and so on.
int i, j;
int numArrayElements;
// for returns
int res;
printf("Enter your paragraphs: ");
// check returns. Always check returns!
// (there are exceptions if you know what you are doing
// or if failure is unlikely under normal circumstances (e.g.: printf()))
// scanf() will read everything that is not a newline up to 1200 characters
res = scanf("%1200[^\n]", userInput);
if (res != 1) {
fprintf(stderr, "Something went wrong with scanf() \n");
exit(EXIT_FAILURE);
}
// you have a string, so use strlen()
// numArrayElements = sizeof(userInput) / sizeof(userInput[0]);
// the return type of strlen() is size_t, hence the cast
numArrayElements = (int) strlen(userInput);
// Checks the char in index 0 to see if its ascii value is equal
// to that of a lowercase letter. If it is, it is capitalized.
// Do yourself a favor and use curly brackets even if you
// theoretically do not need them. The single exception being "else if"
// constructs where it looks more odd if you *do* place the curly bracket
// between "else" and "if"
// don't use the numerical value here, use the character itself
// Has the advantage that no comment is needed.
// But you still assume ASCII or at least an encoding where the characters
// are encoded in a consecutive, gap-less way
if (userInput[0] >= 'a' && userInput[0] <= 'z') {
userInput[0] = capitalize(userInput[0]);
}
// i is set to 1 here because index 0 is taken care of by the
// if statement above this loop
for (i = 1; i < numArrayElements; i++) {
// checks to see if the char at index i has the ascii value of a space.
if (userInput[i] == ' ') {
// checks the char at index i + 1 to see if it has the ascii
// value of a space, as well as the char at index i - 1 to see
// if it is any char other than a period. The latter condition
// is there to prevent a period from being added if one is already present.
if (userInput[i + 1] == ' ' && userInput[i - 1] != '.') {
// If the three conditions above are satisfied, all characters
// in the array at location i and onwards are shifted one index
// to the right. A period is then placed within index i.
// you need to include the NUL at the end, too
for (j = numArrayElements; j > (i - 1); j--) {
userInput[j + 1] = userInput[j];
}
//places a period into index i.
userInput[i] = '.';
// increments numArrayElements to reflect the addition
// of a period to the array.
// numArrayElements might be out of bounds afterwards, needs to be checked
numArrayElements++;
if (numArrayElements > ARRAY_LENGTH) {
fprintf(stderr, "numArrayElements %d out of bounds\n", numArrayElements);
exit(EXIT_FAILURE);
}
// additionally, the char at index i + 3 is examined to see
// if it is capitalized or not.
// The loop has the upper limit at numArrayElements
// i + 3 might be out of bounds, so check
if (i + 3 > ARRAY_LENGTH) {
fprintf(stderr, "(%d + 3) is out of bounds\n",i);
exit(EXIT_FAILURE);
}
if (userInput[i + 3] >= 97 && userInput[i + 3] <= 122) {
userInput[i + 3] = capitalize(userInput[i + 3]);
}
}
}
}
printf("%s\n", userInput);
return 0;
}
char capitalize(char c)
{
// subtracting 32 from a lowercase char should result
// in it gaining the ascii value of its capitalized form.
return (c - ' ');
}