通过 fgets() 接受来自用户的多行输入

Question

我正在尝试从使用 fgets 的用户那里接受多行 'address'，但我在离开 while 循环时遇到了 Segmentation fault (core dumped)。我可以在循环内同时 printf address 和 part_of_address 变量而没有任何问题，而在循环中它按预期工作。一旦摆脱循环，它就会着火。

// Define a char array called 'name' accepting up to 25 characters.
char name[25];
// Define a char array called 'part_of_address' accepting up to 80 characters.
char part_of_address[80];
// Define a char array called 'address' accepting up to 80 characters.
char address[80];

// Clean the buffer, just to be safe...
int c;
while ((c = getchar()) != '\n' && c != EOF) {};

// Ask for the user to enter a name for the record using fgets and stdin, store
// the result on the 'name' char array.
printf("\nEnter the name of the user (RETURN when done):");
fgets(name, 25, stdin);

// Ask for the user to enter multiple lines for the address of the record, capture
// each line using fgets to 'part_of_address'
printf("\nEnter the address of the user (DOUBLE-RETURN when done):");
while (1)
{
    fgets(part_of_address, 80, stdin);
    // If the user hit RETURN on a new line, stop capturing.
    if (strlen(part_of_address) == 1)
    {
        // User hit RETURN
        break;
    }
    // Concatinate the line 'part_of_address' to the multi line 'address'
    strcat(address, part_of_address);
}

printf("This doesn't print...");

Answer 1

正如 Michael Walz 在评论中指出的那样，您甚至在没有初始化 address 的情况下第一次使用 strcat(address, part_of_address);。由于它是一个自动数组，它包含未确定的值，并且您正在调用未定义的行为。甚至第一个 strcat 也可能在 address 数组之后覆盖内存。

只需用char address[80] = "";或char address[80] = {'[=15=]'};

初始化数组

通过 fgets() 接受来自用户的多行输入

Accepting multiple lines of input from user via fgets()

c

fgets

segmentation-fault