Lec4-C intro：Pointers, Arrays, Strings

2024-10-05 132 words One minute

Contents

C intro: Pointers, Arrays, Strings

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int (*fn) (void *, void *) = &foo; // pointer to function

arrow operator -> is used to access members of a struct pointed to by a pointer.

NULL pointer is used to indicate an invalid pointer.

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if (p == NULL) {
    // handle error
}

谈到了地址对齐 -> word alignment

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sizeof(arg)

sizeof(structtype)

经典问题之数组名是指针

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char *foo() {
    char arr[10];
    return arr; 
    // A BIG mistake! 函数栈回收时，arr指针指向的空间可能被释放掉了，导致程序崩溃
}

always end with a null character \0 😉

Segmentation fault :s

或许rust可能更安全

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void incrementPtr(int *p) {
    p += 1;
    // wrong again! have to ...
}

void incrementPtr(int **p) {
    (*p) += 1; // correct
}

注意引用传递即可