Add compare content

2108-compare/Makefile

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+## Simple Makefile by botanicals
+## Code available at https://git.disroot.org/botanicals/blog-files
+
+# Compiler and flags
+CC=gcc
+CFLAGS=-Wall -Wextra -pedantic
+LDLIBS=-lm		# math.h library
+
+# No recipes necessary.
+# `make` builds using implicit rules.

2108-compare/README.md

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+# Compare SHA Sums 
+
+## Idea
+
+I wanted to practice working with files in C programs and at the same time check if the SHA sums for a Manjaro ISO file were the same.
+
+## Prerequisites 
+
+- [GNU make](https://gnu.org/software/make)
+- [gcc](https://gnu.org/software/gcc)
+
+## Usage 
+
+Place the `compare.c` and `Makefile` in the same directory. Build `compare`.
+
+``` sh
+make compare
+```
+
+Either download or create a text file. The first line of the text file should contain only the SHA sum provided by the developer.
+
+Example of `sha-test.txt`:
+
+``` txt
+6ff0ebecb9813542e1fa81bbe897bb59039bb00d 
+```
+
+Append to the file a SHA sum you generated yourself.
+
+``` sh
+sha1sum ISO >> sha-test.txt
+```
+
+Run `compare` and enter the name of the file with SHA sums when prompted.
+
+``` sh
+$ ./compare
+Filename: sha-test.txt
+# The program prints whether SHA sums match or not.
+```
+

2108-compare/compare.c

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+/* Compare by botanicals
+ * Available at https://git.disroot.org/botanicals/blog-files
+ *
+ * This program compares two strings, each in its own line,
+ * of SHA sums read from a file.
+ *
+ * Read the projects README for more details. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main(void)
+{
+    // Declarations
+    FILE *sha;
+    char name[100];
+    char sha1[100];
+    char sha2[100];
+    char c[2];
+
+    // Collect the relevant filename
+    printf("Filename: ");
+    scanf("%s", name);
+
+    // Open file
+    if ((sha = fopen(name, "rt")) == NULL) {
+        printf("Cannot open file!\n");
+        exit(EXIT_FAILURE);
+    }
+
+    // Read the file content; run the compare function
+    fscanf(sha, "%[^\n]", sha1);
+    fscanf(sha, "%[\n]", c);
+    fscanf(sha, "%[^ ]", sha2);
+
+    if (strcmp(sha1, sha2) == 0)
+        printf("SHA sums are the same!\n");
+    else
+        printf("SHA sums are not the same! Do not use.\n");
+
+    // Close file; exit program
+    fclose(sha);
+    return 0;
+}