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好的,我得到了一個文本文件,它有一堆的id,大小和權重。抓取這個數據的函數在底部void listBoxes(const char filename [])。如果用戶輸入1,它應該列出文本文件中的所有信息以及我輸入的一些標題。當我在我的main,case 1中調用函數時,它僅打印標題,並在嘗試打印實際數據時發生錯誤。我知道我只是部分調用了正確的函數,但我不知道如何從函數中獲取數據。調用函數
// Workshop 9 - Files
// Name:
// Student #:
#include <stdio.h>
struct Box
{
int id; // the box ID
double size[3]; // dimensions of the box (Length, Width, Height)
double weight; // weight of the box
};
void printBox(struct Box b)
{
printf("\nID: %6d\n"
"Length: %6.2lf\n"
"Width: %6.2lf\n"
"Height: %6.2lf\n"
"Weight: %6.2lf\n\n", b.id, b.size[0], b.size[1], b.size[2], b.weight);
}
int menu(void)
{
int choice = -1;
printf("1- List all boxes\n");
printf("2- Find a box\n");
printf("3- Add a box\n");
printf("4- Randomly pick a lucky box!\n");
printf("0- Exit program\n");
printf("Select an option: ");
do
{
scanf("%d", &choice);
if (choice < 0 || choice > 4)
printf("Please enter a number between 0 and 4: ");
} while (choice < 0 || choice > 4);
return choice;
}
int main(void)
{
struct Box b;
FILE * fp = NULL;
int choice; // , boxID, r;
char filename[] = "storage.txt";
printf("Welcome to My Storage Room\n");
printf("==========================\n");
do {
// get user's choice
choice = menu();
switch (choice) {
case 1:
// IN_LAB: list items
listBoxes(filename);
break;
case 2:
// IN_LAB: find a box given its ID
// ask for ID
// call displayBox
break;
case 3:
// AT_HOME: add a box
// get user input for box's ID, size and weight
// call addBox, print message to show number of boxes added
break;
case 4:
// AT_HOME: randomly pick a lucky box
// choose a random number between 1 and the number of boxes in storage
// display the lucky box!
break;
};
} while (choice > 0);
return 0;
}
void listBoxes(const char filename[])
{
struct Box b;
FILE * fp = NULL;
fp = fopen("storage.txt", "r");
if (fp != NULL)
{
printf("List of boxes\n");
printf("=============\n");
printf("ID Length Width Height Weight\n");
printf("-----------------------------\n");
fscanf("%2d %6.2lf %5.2lf %6.2lf %6.2lf\n", &b.id, &b.size[0], &b.size[1], &b.size[2], &b.size[3], &b.weight);
fclose(fp);
}
else
{
printf("Error opening file\n");
}
return 0;
}
謝謝。我的教科書說fscanf從文件中讀取,所以我錯誤地認爲閱讀與印刷承擔相同的責任。 –