所以我的文件格式如下:
2
4 8 4 10 6
9 6 74
第一行实际上是文件后面的行数。我想逐行读取文件(注意每行中有不同数量的标记,但都有格式:1个标记,然后是未指定数量的标记对)并为每一行做两件事:
1)知道这一行中有多少令牌。
2)将每个标记分配给变量。使用类似于以下的结构:
typedef struct {
unsigned start; //start node of a graph
unsigned end; // end node of a graph
double weight; //weight of the edge going from start to end
} edge ;
typedef struct {
unsigned id; // id of the node
unsigned ne; // number of edges adjacent to node
edge *edges; // array of edge to store adjacent edges of this node
} node;
一些代码:
FILE *fin;
unsigned nn;
node *nodes;
fin = fopen ("input.txt", "r");
fscanf(fin,"%u\n", &nn);
nodes = malloc(nn*sizeof(node));
for(i=0; i < nn; i++) { //loop through all the rows
/*grab the row and split in parts, let's say they are part[0], part[1]... */
/*and there are N tokens in the row*/
nodes[i].id=part[0];
nodes[i].ne=(N-1)/2; //number of pairs excluding first element
nodes[i].edges=malloc( (N-1)/2)*sizeof(edge) );
for(j=0; j< (N-1)/2; j++){
nodes[i].edges[j].start=part[0];
nodes[i].edges[j].end=part[2*j+1];
nodes[i].edges[j].weight=part[2*j+2];
}
}
我需要弄清楚如何在第一个for循环中进行部分注释,以获取标记的数量,并将每个标记作为一个标记符号进行标记。有什么想法吗?
编辑:为了清楚起见,每一行将有第一个整数,然后是可变数量的对。我想按如下方式存储数据:
如果文件读取
2
4 8 4 10 6 //(2 pairs)
9 6 74 //(1 pair)
然后
nn=2;
node[0].id=4;
node[0].ne=2; //(2 pairs)
node[0].(*edges) //should be a vector of dimension ne=2 containing elements of type edge
node[0].edges[0].start=4; //same as node[0].id
node[0].edges[0].end=8;
node[0].edges[0].weight=4;
node[0].edges[1].start=4; //same as node[0].id
node[0].edges[1].end=10;
node[0].edges[1].weight=6;
node[1].id=9;
node[1].ne=1; //(1 pair)
node[1].(*edges) //should be a vector of dimension ne=1 containing elements of type edge
node[1].edges[0].start=9; //same as node[1].id
node[1].edges[0].end=6;
node[1].edges[0].weight=74;
答案 0 :(得分:2)
此代码生成您描述的结果,它初始化您的嵌套结构成员edge
,并使用strtok。使用strtok()
,除了空格" \n"
之外,我还将\ n作为分隔符的一部分,以防止换行符给我们带来麻烦(请参阅下面的其他评论)
注意: 你必须在我指示的位置释放内存,但在此之前,保留中间结果(在结构中)或者它将丢失。< / p>
#include <ansi_c.h>
typedef struct {
unsigned start;
unsigned end;
double weight;
} edge ;
typedef struct {
unsigned id;
unsigned ne;
edge *edges;
} node;
int GetNumPairs(char *buf);
int main(void)
{
FILE *fp;
char *tok;
char lineBuf[260];
int i=0, j=0;
int nn; //number of nodes
char countPairsBuf[260];
fp = fopen("C:\\dev\\play\\numbers.txt", "r");
//get first line of file for nn:
fgets (lineBuf, sizeof(lineBuf), fp);
nn = atoi(lineBuf);
//create array of node with [nn] elements
node n[nn], *pN;
pN = &n[0];
//read rest of lines, (2 through end)
i = -1;
while(fgets (lineBuf, sizeof(lineBuf), fp))
{
i++;
//get number of items in a line
strcpy(countPairsBuf, lineBuf);
pN[i].ne = GetNumPairs(countPairsBuf); //number of edges (pairs)
if(pN[i].ne > 0)
{ //allocate *edges struct element
pN[i].edges = malloc((pN[i].ne)*sizeof(edge));
//get first item in new line as "line token" and "start"
tok = strtok(lineBuf, " \n");
while(tok)
{
pN[i].id = atoi(tok);
//now get rest of pairs
for(j=0;j<pN[i].ne;j++)
{
pN[i].edges[j].start = pN[i].id;
tok = strtok(NULL, " \n");
pN[i].edges[j].end = atoi(tok);
tok = strtok(NULL, " \n");
pN[i].edges[j].weight = atoi(tok);
}
tok = strtok(NULL, " \n"); //should be NULL if file formatted right
}
}
else //pN[i].ne = -1
{
//error, file line did not contain odd number of elements
}
}
//you have to free memory here
//but I will leave that to you
fclose(fp);
}
//GetNumPairs
int GetNumPairs(char *buf)
{
int len = strlen(buf);
int numWords=0, i, cnt=0;
for(i=0;i<len;i++)
{
if ( isalpha ( buf[i] ) ) cnt++;
else if ( ( ispunct ( buf[i] ) ) || ( isspace ( buf[i] ) ) )
{
numWords++;
cnt = 0;
}
}//if odd number of "words", return number of pairs, else error
return (((numWords-1)%2) == 0) ? ((numWords-1)/2) : (-1);
}