两个大数相加

大数相加考虑到数据长度有限，因此采用字符串的方式进行计算，还要考虑到进位的问题，看下代码：

void big_data_add(char * num1, char * num2)
{
    int length, length1, length2;
    int i, j;
    int intNum1[MAX_LEN] = {0};
    int intNum2[MAX_LEN] = {0};

    if (num1 == NULL || num2 == NULL)
    {
        return;
    }

    length1 = strlen(num1);
    length2 = strlen(num2);

    length = length1 > length2 ? length1 : length2;

    for (j = length, i = 0; i < length1; i++, j--)
    {
        intNum1[j] = num1[length1 - i - 1] - '0';
    }
    for (j = length, i = 0; i < length2; i++, j--)
    {
        intNum2[j] = num2[length2 - i - 1] - '0';
    }

    for (i = length; i >= 0; i--)
    {
        intNum1[i] += intNum2[i];
        if (intNum1[i] >= 10)
        {
            intNum1[i] -= 10;
            intNum1[i - 1]++;
        }
    }

    printf("the sun of num1 and num2 is: ");
    if (intNum1[0] == 0)
    {
        for (i = 1; i <= length; i++)
        {
            printf("%d", intNum1[i]);
        }
    }
    else
    {
        for (i = 0; i <= length; i++)
        {
            printf("%d", intNum1[i]);
        }
    }
    printf("\n");
}

验证程序：

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

#define MAX_LEN 256

int main()
{
    char num1[MAX_LEN];
    char num2[MAX_LEN];

    printf("Enter num1: ");
    gets_s(num1);
    printf("Enter num2: ");
    gets_s(num2);

    big_data_add(num1, num2);

    return 0;
}

输出结果：