elong

numbers/bignum_bin_sum.c

@@ -4,7 +4,7 @@
 int main() {
 	char a[1001] = "";
 	char b[1001] = "";
-	char res[1002] = ""
+	char res[1002] = "";
 	char null = 0;
 	int len, len_;
 	int i, j;

numbers/elong_add.c

@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <stdlib.h>
+#define N 100
+
+struct _Decimal {
+	char a[N];   // number is a[0]*10^0 + a[1]*10^1 + ..+ a[n]*10^n
+	unsigned int n;
+};
+typedef struct _Decimal Decimal;
+
+Decimal zero = {{0}, 0};
+
+Decimal add(Decimal a, Decimal b) {
+	Decimal c;
+	char cf = 0;
+	unsigned int i;
+
+	if (a.n < b.n) {
+		c = a;
+		a = b;
+		b = c;
+	}
+	c.n = a.n;
+	
+	for (i = 0; i <= b.n; ++i) {
+		c.a[i] = (a.a[i] + b.a[i] + cf) % 10;
+		cf = (int)((a.a[i] + b.a[i] + cf) / 10);
+	}
+	
+	for (; i <= a.n; ++i) {
+		c.a[i] = (a.a[i] + cf) % 10;
+		cf = (int)((a.a[i] + cf) / 10);
+	}
+	if (cf) {
+		++c.n;
+		c.a[i] = cf;
+	}
+	return c;
+	
+}
+
+void print(Decimal x) {
+	for (int i = x.n; i >= 0; --i)
+		printf("%d", x.a[i]);
+	printf("\n");
+}
+
+int main(){
+    Decimal b = {{9, 9, 9}, 2};
+    Decimal a = {{2}, 0};
+
+    Decimal res;
+    
+    res = add(a, b);
+    print(res);  
+    return 0;
+}