• ctype means characters type.
• Use of this functions is know which type of characters isdigit(), isalpha() , isupper(), islower()  , spunct().

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isdigit()

• Used to check is character is numeric digit or not.
• Syntax : int isdigit(c); here c is a variable or constant.
• Returns : True – Non-zero, false – Zero.

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isalpha()

• Used to check is character is alphabet or not.
• Syntax : int isalpha(c); here c is a variable or constant.
• Returns : True – Non-zero, false – Zero.

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isupper()

• Used to check is character is upper or not.
• Syntax : int isupper(c); here c is a variable or constant.
• Returns : True – Non-zero, false – Zero.

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islower()

• Used to check is character is lower or not.
• Syntax : int lower(c); here c is a variable or constant.
• Returns : True – Non-zero, false – Zero.

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ispunct()

• Used to check is character is punctuation or not.
• Syntax : int ispunct(c); here c is a variable or constant.
• Returns : True – Non-zero, false – Zero.

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