Reading a well-formatted text file - c

Question

Given the well-formatted text file called input.txt below:
Yesterday snowed
Today is hot
Tomorrow will rain
Next week will earthquake
How can I read the text file line by line and also dynamically allocate memory to each English word as a character array if I do not know the length of each English word since I do not want to waste 1000 bytes on a short word. Should realloc be used in this case? The following is my code:
int main() {
FILE* pfile = fopen("input.txt", "r");
int i = 0;
while (i != 0) {
char* stringLiteral = (char*) malloc(1000 * sizeof(char));
i = fscanf(pfile, "%s", stringLiteral);
insertString(stringLiteral);
}
fclose("input.txt");
return 1;
}
void insertString(char* charArray) {
/*This function inserts a char array to a linked list*/
}

Answer 1

If you want you can use realloc, yes, in that case you would need to reallocate, smaller pieces of memory.
You can even reallocate char by char stretching the string as it's being populated and not waste a single byte.
Example with comments:
Live demo
#include <stdio.h>
#include <stdlib.h>
int main() {
FILE *pfile = fopen("input.txt", "r");
if (pfile == NULL) { //check for errors in opening file
perror("fopen");
}
else {
int c;
int i = 0; //string iterator
char *stringLiteral;
stringLiteral = malloc(1); //initial allocation
if(stringLiteral == NULL) {
perror("malloc");
return EXIT_FAILURE;
}
while ((c = fgetc(pfile)) != EOF) { //until the end of the file is reached
if (c != '\n') { //until the line ends
stringLiteral = realloc(stringLiteral, i + 1); //keep reallocating memory for each character
if(stringLiteral == NULL){
perror("malloc");
return EXIT_FAILURE;
}
stringLiteral[i] = c; //assing the read character to the char array
i++;
}
else { //'\n' was reached
stringLiteral[i] = '\0'; //terminate string
//insertString(stringLiteral); //your insertion function
printf("%s\n", stringLiteral); //test print
i = 0;
}
}
//insertString(stringLiteral); //last read line
printf("%s\n", stringLiteral); // test print
fclose(pfile);
}
return EXIT_SUCCESS;
}
The problem here is that memory allocation is an expensive process and can slow down your program.
You have to weigh what's more important, the space or the speed. Unless the strings are so huge that they cannot fit in the stack, in that case memory allocation is the way to go, though it can be more sensible to allocate blocks of bytes instead of byte by byte.