tolower
From cppreference.com
| Defined in header <ctype.h>
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| int tolower( int ch ); |
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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.
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.
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Return value
Lowercase version of ch or unmodified ch if no lowercase version is listed in the current C locale.
Example
Run this code
#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 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 0xb8References
- C11 standard (ISO/IEC 9899:2011):
- 7.4.2.1 The tolower function (p: 203)