isupper() - Character Function

How is "isupper()" used in C++?

Explanation

isupper() character function is used to check if the argument contains uppercase letters (A-Z). This function returns zero if uppercase letters (A-Z) are not found.

Syntax:


int isupper( int c );

Example :



#include <stdio.h>
#include <ctype.h>
int main ()
{
char arr[]="ABCD.\n";
char c;
for (int i=0; arr[i]!='' ; )
{
if (isupper(c))
{
c='x';
putchar (c);}
i++;
}
return 0;
}

Result :

xxxx.

In the above example, it is used to check the uppercase letters (A-Z) and replace it with lowercase "x". The character check is made using the ctype facet.

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