Add solution for 3 array project

c_modern_approach/Arrays/projects/3_project.c

@@ -0,0 +1,45 @@
+#include <ctype.h>
+#include <stdio.h>
+
+#define MAX_STRING_SIZE 100
+
+int main() {
+  char input[MAX_STRING_SIZE] = {};
+  char filtered[MAX_STRING_SIZE] = {};
+  int last_real_char = 0;
+  printf("Enter message: ");
+  fgets(input, MAX_STRING_SIZE, stdin);
+  for (int i = 0; i < MAX_STRING_SIZE - 1; i++) {
+    char current_char = toupper(input[i]);
+    if (current_char != 0) {
+      last_real_char = i;
+    }
+    switch (current_char) {
+    case 'A':
+      filtered[i] = '4';
+      break;
+    case 'B':
+      filtered[i] = '8';
+      break;
+    case 'E':
+      filtered[i] = '3';
+      break;
+    case 'I':
+      filtered[i] = '1';
+      break;
+    case 'O':
+      filtered[i] = '0';
+      break;
+    case 'S':
+      filtered[i] = '5';
+      break;
+    default:
+      filtered[i] = current_char;
+      break;
+    }
+  }
+  for (int i = last_real_char; i < last_real_char + 10; i++) {
+    filtered[i] = '!';
+  }
+  printf("Entered message: %s", filtered);
+}