c - C中的帕斯卡三角形

我主要是一个Python/MIT方案程序员，但我想学习C，因为我下学期要上一节关于它的课，我想做好准备。我可以说我对python和scheme很在行，所以我不是一般编程新手。是我的一个小朋友：）。
所以我试着写一个C程序来计算帕斯卡三角形，但是它给了我一个错误的输出。我编译时没有错误，下面是我的代码：

/*
  This code is just to see exactly how much faster C is than python
  at doing numerically stuff. It should calculate the nth row of
  pascals triangle.
  The way you use it is by calling the executable with the row
  you wish to compute as the only argument. For example if you
  are on an *nix system:
  ./pascal 6

  Or in a windows command prompt:
  pascal.exe 6
*/

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

/*
  I decided to use a struct here because I thought it was ugly
  to have to pass around the length of my arrays in function
  calls.
*/
typedef struct{
  int length;
  unsigned long int* vals;
} CoolArray;

//initArray allocates memory for the CoolArray.
void initArray(CoolArray* array, int length);

//destroyArray frees allocated memory in the struct.
void destroyArray(CoolArray* array);

//printArray prints the contents of the array.
void printArray(CoolArray* array);

//pascal computes the nth row of pascal's
//triangle, with n being array->length,
//and stores the values in the array.
void pascal(CoolArray* array);

//setArray takes two CoolArrays of the same length
//and sets the values in the first to the values
//in the second.
void setArray(CoolArray* array1, CoolArray* array2);

int main(int argc, char** argv){
  int length = atoi(argv[1]);
  CoolArray array1;
  initArray(&array1, length);
  printf("Calculating the %dth row of pascals triangle...\n", length);
  pascal(&array1);
  printArray(&array1);
  destroyArray(&array1);
  return 0;
}

void initArray(CoolArray* array, int length){
  assert(length>=1); //don't make arrays with a length <=0!!!
  array->length = length;
  array->vals = (unsigned long int*) calloc(length, sizeof(unsigned long int));
  return;
}

void destroyArray(CoolArray* array){
  free(array->vals);
  return;
}

void pascal(CoolArray* array){
  assert(array->length >= 1);//making sure the length wasn't fiddled with...
  if(array->length == 1){
    array->vals[0] = 1;
    return;
  }
  int row;
  int index;
  array->vals[0]=1; //if we aren't looking for the first row
  array->vals[1]=1;//then i'll start with the second row
  CoolArray current;
  initArray(&current, array->length);
  for(row = 2; row < array->length; ++row){
    current.vals[0]=1;
    for(index = 1; index < row; ++index){
      current.vals[index]=array->vals[index]+array->vals[index-1];
    }
    current.vals[row]=1;
    printArray(&current);
    setArray(array, &current);
  }
  destroyArray(&current);
  return;
}

void setArray(CoolArray* array1, CoolArray* array2){
  assert(array1->length==array2->length);//making sure they are the same length
  int i=0;
  for(; i < array2->length; ++i){
    array1->vals[i]=array2->vals[i];
  }
  return;
}

void printArray(CoolArray* array){
  int i=0;
  printf("[");
  for(; i < array->length; ++i){
    if (i = array->length - 1) printf("%d]\n", array->vals[i]);
    else printf("%d, ", array->vals[i]);
  }
  return;
}

有人知道我错在哪里吗？
它的输出现在看起来是这样的：
/帕斯卡6
正在计算帕斯卡三角形的第6行。。。
[一]

最佳答案

您的错误在这一行：

if(array->length = 1){

因为有一个等号，所以将1指定给array->length。使用==进行相等测试，并在编译器中打开警告（-Wall）。
（您在if (i = array->length - 1)行上有一个类似的错误，这会导致您看到的输出格式不正确）。

关于c - C中的帕斯卡三角形，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13061568/