LeetCode: fault list

Posted 2020-11-10 三叁

1. malloc memory should always use the following form:

int *a = malloc(sizeof(int) * 3);
int **b = malloc(sizeof(int*) * 3);
int i = 0;
for (; i < 3; i++) {
    b[i] = malloc(sizeof(int) * 3);
}
char *c = malloc(sizeof(char) * length);
char **pc = malloc(sizeof(char *) * 4);
for (i = 0; i < 4; i++) {
    pc[i] = malloc(sizeof(char) * 3);
}

2. memset memory to 0 should use the form:

// Using the malloced memory above:
memset(a, 0, sizeof(int) * 3);
memset(b, 0, sizeof(int*) * 3);
for (i = 0; i < 3; i++) {
    memset(b[i], 0, sizeof(int) * 3);
}
memset(c, 0, sizeof(char) * 3);
memset(pc, 0, sizeof(char *) * 4);
for (i = 0; i < 4; i++) {
    memset(pc[i], 0, sizeof(char) * 3);
}

3. malloc(0) might also return address which is non-null. Which is error-prone. Consider use the following malloc. (..my implementation, any suggestion?)

#define SMALLOC(x)       \
({                                   void *addr;                       if ((x) == 0)                   addr = 0;                       else addr = malloc(x);     (addr);                           })