Fixed many minor things, tested it on main and is amazing, i think i need to start adding fractions next so further testing can be done with more powerful operators

src/main.c

@@ -1,16 +1,30 @@
+#include "evaluator.h"
 #include "lexer.h"
 #include "parser.h"
+#include <stdint.h>
+#include <inttypes.h>
 #include <stdlib.h>
 #include <stdio.h>
 
 int main(void) {
-    ASTNodeArray context;
+    char buf[256];
+    printf("Insert a valid mathematical expression: ");
+    
+    int c;
+    int pos = 0;
+    while ((c = getc(stdin)) != '\n' && c != EOF) {
+        buf[pos] = c;
+        pos++;
+    }
+    buf[pos] = '\0';
 
-    tokenize("3 + 4 * 5", &context);
+    ASTNodeArray context;
+    tokenize(buf, &context);
 
     AST tree = parse(&context);
+    int64_t result = evaluate(tree.head);
 
-    printf("Hola\n");
 
+    printf("El resultado es: %" PRIi64 "\n", result);
     return EXIT_SUCCESS;
 }