我正在尝试查找大数的总和。(100 位,1500 位)
有我的求和函数:
char *find_sum(char *a, char *b) {
char *res;
int alen, blen, rlen;
int carry;
alen = strlen(a);
blen = strlen(b);
rlen = 1 + ((alen > blen) ? alen : blen);
res = malloc(1 + rlen);
if (res) {
int oldlen = rlen;
res[rlen] = 0;
carry = 0;
while (rlen) {
int tmp;
if (alen && blen) tmp = a[--alen] - '0' + b[--blen] - '0';
else if (alen) tmp = a[--alen] - '0';
else if (blen) tmp = b[--blen] - '0';
else tmp = 0;
tmp += carry;
res[--rlen] = '0' + tmp % 10;
carry = tmp / 10;
}
if (res[0] == '0') memmove(res, res+1, oldlen);
}
return res;
}
如果我尝试如下所示,代码正在运行:
char a[] = "243432423423423";
char b[] = "74356348775345";
char *c;
c = find_sum(a,b);
printf("%s",c);
但我想从文件中(按行)获取这些数字(a 和 b)。例如,我的 data.txt 有以下几行:
7326473264723672364723864762374236
32473264623748632784632784
432423432423423423
0
3248972389473289473289478923
4897238473247382
732468723647236478238423
0
432748932489327894723894798239
48327489237483278
0
32423423423423
我想打开这个文件,读取每一行和所有数字的总和(如果达到 0 则停止并写入其他文件 sum.txt)
如果我尝试使用fgets从文件中添加值,则会出现类型不兼容的错误。
我的测试代码:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
char *find_sum(char *a, char *b);
int main(int argc, const char *argv[])
{
FILE *file;
file = fopen("a.txt", "r");
if (file != NULL){
char *buf;
char *buf1;
char *sum;
fgets(buf, 100, file);
fgets(buf1, 100, file);
sum = find_sum(buf, buf1);
printf("%s",sum);
}
fclose(file);
return 0;
}
char *find_sum(char *a, char *b) {
char *res;
int alen, blen, rlen;
int carry;
alen = strlen(a);
blen = strlen(b);
rlen = 1 + ((alen > blen) ? alen : blen);
res = malloc(1 + rlen);
if (res) {
int oldlen = rlen;
res[rlen] = 0;
carry = 0;
while (rlen) {
int tmp;
if (alen && blen) tmp = a[--alen] - '0' + b[--blen] - '0';
else if (alen) tmp = a[--alen] - '0';
else if (blen) tmp = b[--blen] - '0';
else tmp = 0;
tmp += carry;
res[--rlen] = '0' + tmp % 10;
carry = tmp / 10;
}
if (res[0] == '0') memmove(res, res+1, oldlen);
}
return res;
}