普通大数运算
对于不同的题目要求，在main函数里修改就可以了
const int MAXSIZE = 200;
void Add(char *str1, char *str2, char *str3);
void Minus(char *str1, char *str2, char *str3);
void Mul(char *str1, char *str2, char *str3);
void Div(char *str1, char *str2, char *str3);
int main()
{
char str1[MAXSIZE], str2[MAXSIZE], str3[MAXSIZE];
while (scanf("%s %s", str1, str2) == 2)
{
if (strcmp(str1, "0"))
{
memset(str3, '0', sizeof(str3));
Add(str1, str2, str3);
printf("%s\n", str3);
memset(str3, '0', sizeof(str3));
Minus(str1, str2, str3);
printf("%s\n", str3);
memset(str3, '0', sizeof(str3));
Mul(str1, str2, str3);
printf("%s\n", str3);
memset(str3, '0', sizeof(str3));
Div(str1, str2, str3);
printf("%s\n", str3);
}
else
{
if (strcmp(str2, "0"))
{
printf("%s\n-%s\n0\n0\n", str2, str2);
}
else
{
printf("0\n0\n0\n0\n");
}
}
}
return 0;
}
void Add(char *str1, char *str2, char *str3)
{
int i, j, i1, i2, tmp, carry;
int len1 = (int)strlen(str1), len2 = (int)strlen(str2);
char ch;
i1 = len1 - 1;
i2 = len2 - 1;
j = carry = 0;
for (; i1 >= 0 && i2 >= 0; ++j, --i1, --i2)
{
tmp = str1[i1] - '0' + str2[i2] - '0' + carry;
carry = tmp / 10;
str3[j] = tmp % 10 + '0';
}
while (i1 >= 0)
{
tmp = str1[i1--] - '0' + carry;
carry = tmp / 10;
str3[j++] = tmp % 10 + '0';
}
while (i2 >= 0)
{
tmp = str2[i2--] - '0' + carry;
carry = tmp / 10;
str3[j++] = tmp % 10 + '0';
}
if (carry)
{
str3[j++] = carry + '0';
}
str3[j] = '\0';
for (i = 0, --j; i < j; ++i, --j)
{
ch = str3[i];
str3[i] = str3[j];
str3[j] = ch;
}
return ;
}
void Minus(char *str1, char *str2, char *str3)
{
int i, j, i1, i2, tmp, carry;
int len1 = (int)strlen(str1), len2 = (int)strlen(str2);
char ch;
i1 = len1 - 1;
i2 = len2 - 1;
j = carry = 0;
while (i2 >= 0)
{
tmp = str1[i1] - str2[i2] - carry;
if (tmp < 0)
{
str3[j] = tmp + 10 + '0';
carry = 1;
}
else
{
str3[j] = tmp + '0';
carry = 0;
}
i1--;
i2--;
j++;
}
while (i1 >= 0)
{
tmp = str1[i1] - '0' - carry;
if (tmp < 0)
{
str3[j] = tmp + 10 + '0';
carry = 1;
}
else
{
str3[j] = tmp + '0';
carry = 0;
}
--i1;
++j;
}
--j;
while (str3[j] == '0' && j > 0)
{
--j;
}
str3[++j] = '\0';
for (i = 0, --j; i < j; ++i, --j)
{
ch = str3[i];
str3[i] = str3[j];
str3[j] = ch;
}
return ;
}
void Mul(char *str1, char *str2, char *str3)
{
int i, j = 0, i1, i2, tmp, carry, jj;
int len1 = (int)strlen(str1), len2 = (int)strlen(str2);
char ch;
jj = carry = 0;
for (i1 = len1 - 1; i1 >= 0; --i1)
{
j = jj;
for (i2 = len2 - 1; i2 >= 0; --i2, ++j)
{
tmp = (str3[j] - '0') + (str1[i1] - '0') * (str2[i2] - '0') + carry;
if (tmp > 9)
{
carry = tmp / 10;
str3[j] = tmp % 10 + '0';
}
else
{
str3[j] = tmp + '0';
carry = 0;
}
}
if (carry)
{
str3[j] = carry + '0';
carry = 0;
j++;
}
jj++;
}
j--;
while (str3[j] == '0' && j > 0)
{
j--;
}
str3[++j] = '\0';
for (i = 0, --j; i < j; ++i, --j)
{
ch = str3[i];
str3[i] = str3[j];
str3[j] = ch;
}
return ;
}
void Div(char *str1, char *str2, char *str3)
{
int i1, i2, i, j, jj = 0, tag, carry, cf, c[MAXSIZE];
int len1 = (int)strlen(str1), len2 = (int)strlen(str2), lend;
char d[MAXSIZE];
memset(c, 0, sizeof(c));
memcpy(d, str1, len2);
lend = len2;
j = 0;
for (i1 = len2 - 1; i1 < len1; ++i1)
{
if (lend < len2)
{
d[lend] = str1[i1+1];
c[j] = 0;
++j;
++lend;
}
else if (lend == len2)
{
jj = 1;
for (i = 0; i < lend; ++i)
{
if (d[i] > str2[i])
{
break;
}
else if (d[i] < str2[i])
{
jj = 0;
break;
}
}
if (jj == 0)
{
d[lend] = str1[i1+1];
c[j] = 0;
++j;
++lend;
continue;
}
}
if (jj == 1 || lend > len2)
{
cf = jj = 0;
while (d[jj] <= '0' && jj < lend)
{
++jj;
}
if (lend - jj > len2)
{
cf = 1;
}
else if (lend - jj < len2)
{
cf = 0;
}
else
{
i2 = 0;
cf = 1;
for (i = jj; i < lend; ++i)
{
if (d[i] < str2[i2])
{
cf = 0;
break;
}
else if (d[i] > str2[i2])
{
break;
}
++i2;
}
}
while (cf)
{
i2 = len2 - 1;
cf = 0;
for (i = lend - 1; i >= lend - len2; --i)
{
d[i] = d[i] - str2[i2] + '0';
if (d[i] < '0')
{
d[i] = d[i] + 10;
carry = 1;
--d[i - 1];
}
else
{
carry = 0;
}
--i2;
}
++c[j];
jj = 0;
while (d[jj] <= '0' && jj < lend)
{
++jj;
}
if (lend - jj > len2)
{
cf = 1;
}
else if (lend - jj < len2)
{
cf = 0;
}
else
{
i2 = 0;
cf = 1;
for (i = jj; i < lend; ++i)
{
if (d[i] < str2[i2])
{
cf = 0;
break;
}
else if (d[i] > str2[i2])
{
break;
}
++i2;
}
}
}
jj = 0;
while (d[jj] <= '0' && jj < lend)
{
++jj;
}
for (i = 0; i < lend - jj; ++i)
{
d[i] = d[i + jj];
}
d[i] = str1[i1 + 1];
lend = i + 1;
j++;
}
}
i = tag = 0;
while (c[i] == 0)
{
++i;
}
for (; i < j; ++i, ++tag)
{
str3[tag] = c[i]+'0';
}
str3[tag] = '\0';
return ;
}