c++笔试面试之数据结构与算法

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// The strcpy() function copies the string pointed to by src, including the terminating null byte ('\0'), to the buf

// pointed to by dest. The strings may not overlap, and the destination string dest must be large enough to receive

copy.

char *strcpy(char *dest, const char *src)

{

assert((src != NULL) && (dest != NULL));

size_t i;

for (i = 0; src[i] != '\0'; i++)

dest[i] = src[i];

// the string placed in dest will not be null-terminated. If the length of src is less than n, strncpy() pads the remainde

dest with null bytes.

char *strncpy(char *dest, const char *src, size_t n)

{

assert((src != NULL) && (dest != NULL));

size_t i;

for (i = 0; i < n && src[i] != '\0'; i++)

dest[i] = src[i];

for (; i < n; i++)

dest[i] = '\0';

{

assert((src != NULL) && (dest != NULL));

char *d = dest;

const char *s = src;

int *di;

const int *si;

int r = n % 4;

while (r--)

*d++ = *s++;

di = (int *)d;

C++ Code

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size_t strlen(const char *p)

{

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size_t size = 0;

while (*p++ != '\0')

++size;

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size_t i;

for (i = 0 ; i < n && src[i] != '\0' ; i++)

dest[dest_len + i] = src[i];

dest[dest_len + i] = '\0';

return dest;

}

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{

++ s;

++ t;

}

return(*s - *t);

}