C Standard Library__library

C Standard Library

Strchr

Purpose:

Searches a string for a given character, which may

The null character '/0 '.

Entry:

Char *string-string to search in

Char C-character to search for

Exit:

Returns pointer to the ' the ' of C in string

Returns NULL if C does not occur in string

Char *STRCHR (

const char * string,

int CH

)

{

while (*string && *string!= (char) ch)

string++;

if (*string = = (char) ch)

Return ((char *) string);

return (NULL);

}

Strlen

Purpose:

Finds the length in bytes of the given string, not

Including the final null character.

Entry:

const char * str-string whose length is to be computed

Exit:

Length of the string "str", exclusive of the final null

Byte

size_t strlen (

const char * str

)

{

const char *eos = str;

while (*eos++);

return ((int) (eos-str-1));

}

strcpy

Purpose:

Copies the string src into the spot specified by

Dest Assumes enough room.

Entry:

char * dst-string over which ' src ' is ' to ' copied

const char * src-string to is copied over "DST"

Exit:

The address of "DST"

Char *strcpy (char * DST, const char * src)

{

char * cp = DST;

while (*cp++ = *src++)

; /* Copy src over DST * *

return (DST);

}

strcmp

Purpose:

STRCMP compares two strings and returns an integer

To indicate whether the less than the second,

The two are equal, or whether the ' the ' is greater than

The second.

Comparison is doing byte by byte on a UNSIGNED basis,

Which is to say so Null (0) is less than no other

Character (1-255).

Entry:

const char * src-string for left-hand side of comparison

const char * dst-string for right-hand side of comparison

Exit:

returns-1 if SRC < DST

returns 0 if src = DST

Returns +1 if src > DST

int strcmp (

const char * src,

const char * DST

)

{

int ret = 0;

while (! (ret = * (unsigned char *) src-* (unsigned char *) DST) && *DST)

++SRC, ++DST;

if (Ret < 0)

ret =-1;

else if (Ret > 0)

ret = 1;

return (ret);

}

Strcat

Purpose:

Concatenates src onto the end of Dest. Assumes enough

Spaces in Dest.

Entry:

Char *dst-string to which ' src ' is ' to ' appended

const char *src-string to is appended to "end of"

"DST"

Exit:

The address of "DST"

char * __cdecl strcat (

char * DST,

const char * src

)

{

char * cp = DST;

while (*CP)

cp++; /* Find end of DST * *

while (*cp++ = *src++); /* Copy src to end of DST * *

return (DST); /* RETURN DST * *

}