C语言转换字符串为大写和小写
#include <ctype.h>
/*
* Convert a string to lowercase
*/
char *lc(char *str)
{
char *t;
for (t = str; *t; t++)
{
/* Convert to lowercase */
(*t) = tolower(*t);
}
/* Done */
return (str);
}
/*
* Convert a string to uppercase
*/
char *uc(char *str)
{
char *t;
for (t = str; *t; t++)
{
/* Convert to uppercase */
(*t) = toupper(*t);
}
/* Done */
return (str);
}
