Write a C program using (1) arrays and then (2) pointers with malloc() and free(

Question

Write a C program using (1) arrays and then (2) pointers with malloc() and free() functions to

(A1) Open a file, read and print line by line.

(A2) Open a file, read only integers (max 300 numbers) from that file into an array, and print out the array in the reverse order.

(A3) Open a file, read all numbers (floating point is fine) into an array and return those that are strictly less than their two neighbors.

(A4). Get two integers n and m from the user, generate two n-by-m matrices and add/subtract one from another. Print out both matrices and the resulting one.

Explanation / Answer

Hi,
There are 4 different program questions in this, as per chegg policy, we are supposed to answer only one per answer, please post others as a separate question, we will be happy to assist you :)
answering the 1st part here, below is the code with comments to help you understand.
#include <stdio.h>
int main ()
{
char filename[] = "file.txt";//your file name here
FILE *file = fopen ( filename, "r" );//open for reading
if ( file != NULL )
{
char line [128]; // max size of line to be given here
while ( fgets ( line, sizeof line, file ) != NULL ) /* read a line*/
{
fputs ( line, stdout ); // printing the line
}
fclose ( file );//closing the file pointer
}
else
{
printf("error while opening file");
}
return 0;
}
Thumbs up if this was helpful, otherwise let me know in comments

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