C / C ++the ungetc()

This functionungetc()Get a character and push it back into the stream so that it can be read again.

Thisungetc()C Language Syntax

int ungetc(int character, FILE　*stream)

Here,

character-the character to be pushed back into the stream.

stream-is a pointer to a file object.

Thisungetc()C Language Example

Example

#include <stdio.h>
int main() {
　　　int c;
　　　while ((c = getchar()) != '0')
　　　putchar(c);
　　　ungetc(c, stdin);
　　　c = getchar();
　　　putchar(c);
　　　puts("");
　　　printf("End!");
　　　return 0;
}

Output Result

s a b c t h 0
End!

In the above program, an int type character is declared. It will read characters until it encounters 0/It will display the character and print "The End!" when it encounters zero.

int c;
while ((c = getchar()) != '0')
putchar(c);
ungetc(c, stdin)
c = getchar();
putchar(c);
puts("");
printf("End!");