我使用的是旧式乘法方法来计算阶乘,但是对于大于13的数字,我仍然得到错误的答案。我知道没有数据类型可以准确地容纳这么大的值,因此我使用数组将数字存储在分别编号。
代码中的“ cas”表示要计算阶乘的数量。
这是代码-
void factorial (int cas)
{
int num[158];
num[0] = 1;
for (int i=1; i<158; i++)
{
num[i] = 0;
}
int row1[158];
int row2[158];
int length = 0;
int max = 0;
int carry = 0;
for (int j=1; j<=cas; j++)
{
for (int i=0; i<158; i++)
{
row1[i] = 0;
row2[i] = 0;
}
for (length=157; length>=0; length--)
{
if (num[length] != 0)
break;
}
if (j/10 < 1)
{
int* ptr = num;
carry = 0;
for (int i=0; i<=length; i++)
{
int mult = (j * num[i]) + carry;
int units = mult % 10;
carry = mult / 10;
*ptr = units;
ptr++;
}
*ptr = carry;
}
else
{
int* ptr = num;
int* ptr1 = row1;
row2[0] = 0;
int* ptr2 = row2 + 1;
carry = 0;
for (int i=0; i<=length; i++)
{
int mult = ((j%10) * num[i]) + carry;
int units = mult % 10;
carry = mult / 10;
*ptr1 = units;
ptr1++;
}
*ptr1 = carry;
for (int i=0; i<=length; i++)
{
int mult = ((j/10) * num[i]) + carry;
int units = mult % 10;
carry = mult / 10;
*ptr2 = units;
ptr2++;
}
*ptr2 = carry;
for (max=157; max>=0; max--)
{
if (row1[max] != 0 || row2[max] != 0)
break;
}
carry = 0;
for (int i=0; i<=max; i++)
{
int add = row1[i] + row2[i] + carry;
int units = add % 10;
carry = add / 10;
*ptr = units;
ptr++;
}
*ptr = carry;
}
}
for (length=157; length>=0; length--)
{
if (num[length] != 0)
break;
}
for (;length>=0;length--)
{
printf("%i",num[length]);
}
printf("\n");
}
最佳答案
您忘了将进位乘以数字的十分之一,然后将进位重置为0。
}
*ptr1 = carry;
carry = 0; // ADDED LINE: Reset carry before multiplying with the tens part
for (int i=0; i<=length; i++)
{
int mult = ((j/10) * num[i]) + carry;
关于c - 我的代码中计算不超过99的阶乘的错误在哪里?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/39224407/