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tolower

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Revision as of 04:38, 9 May 2014 by Newatthis (Talk | contribs)

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Defined in header <ctype.h>
int tolower( int ch );

Converts the given character to lowercase according to the character conversion rules defined by the currently installed C locale.

In the default "C" locale, the following uppercase letters ABCDEFGHIJKLMNOPQRSTUVWXYZ are replaced with respective lowercase letters abcdefghijklmnopqrstuvwxyz.

Contents

[edit] Parameters

ch - character to be converted. If the value of ch is not representable as unsigned char and does not equal EOF, the behavior is undefined.

[edit] Return value

Lowercase version of ch or unmodified ch if no lowercase version is listed in the current C locale.

[edit] Example

#include <stdio.h>
#include <ctype.h>
#include <locale.h>
#include <limits.h>
 
int main(void)
{
    /* In the default locale: */
    unsigned char l;
    for (unsigned char u=0; u<UCHAR_MAX; u++) {
        l = tolower(u);
        if (l!=u) printf("%c%c ", u,l);
    }
    printf("\n\n");
 
    unsigned char c = '\xb4'; // the character Ž in ISO-8859-15
                              // but ´ (acute accent) in ISO-8859-1 
    unsigned char c2 = c;   // for printing
    setlocale(LC_ALL, "en_US.iso88591");
    printf("in iso8859-1, tolower('0x%x') gives 0x%x\n", c2, tolower(c));
    setlocale(LC_ALL, "en_US.iso885915");
    printf("in iso8859-15, tolower('0x%x') gives 0x%x\n", c2, tolower(c));
}

Output:

Aa Bb Cc Dd Ee Ff Gg Hh Ii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww Xx Yy Zz
 
in iso8859-1, tolower('0xb4') gives 0xb4
in iso8859-15, tolower('0xb4') gives 0xb8

[edit] See also

converts a character to uppercase
(function) [edit]
converts a wide character to lowercase
(function) [edit]
C++ documentation for tolower