CodingUnit Programming Tutorials » C Reference ctype.h Functions

C Reference Convert to upper case: toupper()

admin — Thu, 23 Jul 2009 08:29:20 +0000

The function toupper() returns a uppercase character of the character that is put in. toupper() source code example: #include<stdio.h> #include<ctype.h> int main() { int counter=0; char mychar; char str[]="TeSt THis seNTeNce.\n"; while (str[counter]) { mychar=str[counter]; putchar (toupper(mychar)); counter++; } return 0; } Note: the sentence will be converted to all uppercase letters. C Reference Convert [...]

C Reference Convert to upper case: toupper() is a post from: CodingUnit Programming Tutorials

C Reference Convert to lower case: tolower()

admin — Thu, 23 Jul 2009 08:27:08 +0000

The function tolower() returns a lowercase character of the character that is put in. tolower() source code example: #include<stdio.h> #include<ctype.h> int main() { int counter=0; char mychar; char str[]="TeSt THis seNTeNce.\n"; while (str[counter]) { mychar=str[counter]; putchar (tolower(mychar)); counter++; } return 0; } Note: the sentence will be converted to all lowercase letters. C Reference Convert [...]

C Reference Convert to lower case: tolower() is a post from: CodingUnit Programming Tutorials

C Reference Hexidecimal Digit Test: isxdigit()

admin — Thu, 23 Jul 2009 08:25:30 +0000

The function isxdigit() returns a non-zero if its argument is a hexadecimal digit. (If the argument is a: a-f, A-F, or 0-9). If the argument is not a hexadecimal digit, then zero is returned. isxdigit() source code example: #include<stdio.h> #include<ctype.h> int main() { char a; scanf( "%c", &a ); if( isxdigit(a) ) printf( "Is a [...]

C Reference Hexidecimal Digit Test: isxdigit() is a post from: CodingUnit Programming Tutorials

C Reference Upper case letter test: isupper()

admin — Thu, 23 Jul 2009 08:23:53 +0000

The isupper() function returns a non-zero if its argument is an uppercase letter. If the argument is not an uppercase letter, then zero is returned. isupper() source code example: #include<stdio.h> #include<ctype.h> int main() { char a; scanf( "%c", &a ); if( isupper(a) ) printf( "This is an uppercase letter: %c\n", a ); else printf( "This [...]

C Reference Upper case letter test: isupper() is a post from: CodingUnit Programming Tutorials

C Reference Space, formfeed, newline, etc test: isspace()

admin — Thu, 23 Jul 2009 08:22:48 +0000

The isspace() function returns a non-zero if its argument is a single space, newline, tab, form feed, vertical tab, or carriage return. If the argument is not a single space, newline, tab, form feed, vertical tab, or carriage return , then zero is returned. isspace() source code example: #include<stdio.h> #include<ctype.h> int main() { int newchar; [...]

C Reference Space, formfeed, newline, etc test: isspace() is a post from: CodingUnit Programming Tutorials

C Reference Punctuation Character: ispunct()

admin — Thu, 23 Jul 2009 08:21:15 +0000

The ispunct() function returns a non-zero if its argument is a punctuation character. (All characters except alphanumeric or white-space). If the argument is not a punctuation character, then zero is returned. ispunct() source code example: #include<stdio.h> #include<ctype.h> int main() { int counter=0; int counter2=0; char str[]="Hello, World!!"; while (str[counter]) { if (ispunct(str[counter])) counter2++; counter++; } [...]

C Reference Punctuation Character: ispunct() is a post from: CodingUnit Programming Tutorials

C Reference Printing Character: isprint()

admin — Thu, 23 Jul 2009 08:20:18 +0000

The function isprint() returns a non-zero if its argument is a printable character (including a white-space). If the argument is not a printable character (like the newline character ‘\n’ ) , then zero is returned. isprint() source code example: #include<stdio.h> #include<ctype.h> int main() { int counter=0; char str[]="line one \n line two \n line three [...]

C Reference Printing Character: isprint() is a post from: CodingUnit Programming Tutorials

C Reference Lower Case Letter Test: islower()

admin — Thu, 23 Jul 2009 08:19:12 +0000

The islower() function returns a non-zero if its argument is a lowercase letter. If the argument is not a lowercase letter, then zero is returned. islower() source code example: #include<stdio.h> #include<ctype.h> int main() { char a; scanf( "%c", &a ); if( islower(a) ) printf( "Is lower case: %c\n", a ); else printf( "Is NOT lower [...]

C Reference Lower Case Letter Test: islower() is a post from: CodingUnit Programming Tutorials

C Reference Printing Character Test (not space): isgraph()

admin — Thu, 23 Jul 2009 08:18:04 +0000

The function isgraph() checks if parameter is a character with graphical representation that can be printed. Whitespace characters like space are skipped. If the argument is not, then zero is returned. isgraph() source code example: #include<stdio.h> #include<ctype.h> int main() { FILE * ptr_file; int a; ptr_file=fopen ("file.txt","r"); if (ptr_file) { do { a = fgetc [...]

C Reference Printing Character Test (not space): isgraph() is a post from: CodingUnit Programming Tutorials

C Reference Decimal Digit Test: isdigit()

admin — Thu, 23 Jul 2009 08:15:18 +0000

The function isdigit() returns a non-zero if its argument is a digit between 0 and 9. If its argument is not a digit between 0 and 9, then zero is returned. isdigit() source code example: #include<stdio.h> #include<ctype.h> int main() { char a; scanf( "%c", &a ); if( isdigit(a) ) printf( "This is a digit: %c\n", [...]

C Reference Decimal Digit Test: isdigit() is a post from: CodingUnit Programming Tutorials