fscanf wont work. will have to map the file to an array and parse it manually.

3/inputDemo

@@ -0,0 +1 @@
+xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))

3/main.c

@@ -0,0 +1,35 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#define LINES 1000
+
+int parse_numbers(char *mulString, int *a, int *b)
+{
+	int i = 4;
+	while (mulString[i] >= '0' && mulString[i] <= '9') {
+		*a = *a * 10 + mulString[i] - '0';
+		i++;
+	}
+	i++;
+	while (mulString[i] >= '0' && mulString[i] <= '9') {
+		*b = *b * 10 + mulString[i] - '0';
+		i++;
+	}
+	return 1;
+}
+
+int main()
+{
+	int sum = 0;
+	char mulString[32];
+	
+	FILE *input;
+	input = fopen("./inputDemo", "r");
+	int a = 0;
+	int b = 0;
+	while (fscanf(input, "%d,%d", &a, &b)) {
+		sum += a * b;
+	}
+	printf("%d, %d\n", a, b);
+	printf("%d\n", sum);
+}