big_num_sum

numbers/bignum_bin_sum.c

@@ -0,0 +1,81 @@
+#include <stdio.h>
+#include <string.h>
+
+int main() {
+	char a[1001] = "";
+	char b[1001] = "";
+	char res[1002] = ""
+	char null = 0;
+	int len, len_;
+	int i, j;
+	
+	char cf = 0;
+
+	scanf("%s", a);
+	scanf("%s", b);
+
+	j = 0;
+	if (a[0] == '0') 
+		null = 1;
+	if (null) {
+		for (i = 0; (i <= (int)strlen(a)) && (a[i] != '\0'); ++i) {
+	
+			if (!null || a[i] != '0') {
+				res[j] = a[i];
+				++j;
+				null = 0;
+			}
+		}
+		strcpy(a, res);
+	}
+	if (null) {
+		a[0] = '0';
+		a[1] = '\0';
+	}
+
+	null = 0;
+	j = 0;
+	if (b[0] == '0') 
+		null = 1;
+	if (null) {
+		for (i = 0; (i <= (int)strlen(b)) && (b[i] != '\0'); ++i) {
+			if (!null || b[i] != '0') {
+				res[j] = b[i];
+				++j;
+				null = 0;
+			}
+		}
+		strcpy(b, res);
+	}
+	if (null) {
+		b[0] = '0';
+		b[1] = '\0';
+	}
+	if (strlen(a) < strlen(b)) {
+		strcpy(res, a);
+		strcpy(a, b);
+		strcpy(b, res);
+	}
+	len = strlen(a);
+	len_ = strlen(b);
+	strcpy(res, b);
+	for (i = 0; i < len-len_; ++i) {
+		b[i] = '0';
+	}
+	for (i = 0; i < len_+1; ++i) {
+		b[len-i] = res[len_-i];
+	}
+
+	for (i = len-1; i >= 0; --i) {
+		res[i] = '0' + (a[i] + b[i] - 2 * '0' + cf) % 2;
+		cf = (int)((a[i] + b[i] - 2 * '0' + cf) / 2);
+	}
+
+	if (cf) {
+		putchar('1');
+		printf("%s", res);
+		return 0;
+	}
+	printf("%s", res);
+	return 0;
+}