c - Fscanf 读取 c 中 float 和字符的混合

Question

所以我有一个 .txt 文件，如下所示:

** Paris ** Flight,5 days,visiting various monuments. | 2999.99 |
** Amsterdam ** By bus,7 days, local art gallery. | 999.99 |
** London ** Flight,3 days,lots of free time. | 1499.99 |

我想获取存储在 3 个变量中的信息，城市、描述和价格，但我根本无法保存这些行。

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

int main()
{
    FILE *fp;
    char city[256],desciption[256];
    float temp;
    if(fp=fopen("Ponuda.txt","rt")==NULL){
        printf("ERROR\n");
        exit(1);
    }

    while(fscanf(fp,"** %s ** %s | %f |",city,description,&temp)==3){

        printf("** %s ** %s |%f|\n",city,description,temp);
    }
    return 0;

Answer 1

IMO 使用fgets 读取每一行文件要容易得多，然后使用strtok 用分隔符字符串"*|"< 分割每一行.

然后我使用 strdup 将文本字符串复制到结构中，并使用 sscanf 从第三个标记中提取票价。我应该测试 strdup 的返回值，因为它在内部调用了 malloc。

我还使用 double 而不是 float(我只会在有约束的情况下使用它)。

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

#define MAX  10

typedef struct {
    char *city;
    char *descrip;
    double fare;
} flight_t;

int main()
{
    FILE *fp;
    flight_t visit[MAX] = {0};
    char buffer [1024];
    char *tok;
    int records = 0, i;
    if((fp = fopen("Ponuda.txt", "rt")) == NULL) {
        printf("Error opening file\n");
        exit(1);
    }

    while(fgets(buffer, sizeof buffer, fp) != NULL) {
        if((tok = strtok(buffer, "|*")) == NULL) {
            break;
        }
        if(records >= MAX) {
            printf("Too many records\n");
            exit(1);
        }
        visit[records].city = strdup(tok);          // add NULL error checking

        if((tok = strtok(NULL, "|*")) == NULL) {    // pass NULL this time
            break;
        }
        visit[records].descrip = strdup(tok);       // add NULL error checking

        if((tok = strtok(NULL, "|*")) == NULL) {    // pass NULL this time
            break;
        }
        if(sscanf(tok, "%lf", &visit[records].fare) != 1) {     // read a double
            break;
        }
        records++;
    }

    fclose(fp);

    // print the records
    for(i = 0; i < records; i++) {
        printf("** %s ** %s |%.2f|\n", visit[i].city, visit[i].descrip, visit[i].fare);
    }

    // free the memory given by strdup
    for(i = 0; i < records; i++) {
        free(visit[i].city);
        free(visit[i].descrip);
    }
    return 0;
}

程序输出:

**  Paris  **  Flight,5 days,visiting various monuments.  |2999.990000|
**  Amsterdam  **  By bus,7 days, local art gallery.  |999.990000|
**  London  **  Flight,3 days,lots of free time.  |1499.990000|