题解 | #a+b#

#include<stdio.h>
#include<string.h>

char str1[1001], str2[1001];
int a[1001], b[1001];

int convert(char str[], int
            num[]) {    //将字母转变为数字，按照低位到高位存放
    int len = strlen(str);
    for (int i = 0; i < len; i++)
        num[i] = str[len - i - 1] - '0';
    return len;
}

int main() {
    int n1, n2, n;
    while (scanf("%s%s", str1, str2) != EOF) {
        int flag = 0;   //数组置0，flag为进位
        n1 = convert(str1, a);
        n2 = convert(str2, b);
        n = n1 >= n2 ? n1 : n2;
        for (int i = 0; i < n; i++) {
            int temp = (a[i] + b[i] + flag) /
                       10;      //商为进位，余数为当前位结果
            a[i] = (a[i] + b[i] + flag) % 10;
            flag = temp;
        }
        if (flag) a[n++] = flag;                       //最高位产生进位
        for (int i = n - 1; i >= 0; i--) printf("%d", a[i]);
        printf("\n");
    }
    return 0;
}