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─────Run-Time Library───────────────────────────────────────────────────────
 
/* UNGET.C illustrates getting and ungetting characters from the console.
 * Functions illustrated include:
 *      _getch           _ungetch         _putch
 */
 
#include <conio.h>
#include <stdio.h>
#include <ctype.h>
 
void skiptodigit( void );
int getnum( void );
 
void main()
{
    int c, array[5];
 
    /* Get five numbers from console. Then display them. */
    printf( "Enter five numbers:\n" );
    for( c = 0; c < 5; c++ )
    {
        skiptodigit();
        array[c] = getnum();
        printf( "\t" );
    }
    for( c  = 0; c < 5; c++ )
        printf( "\n\r%d", array[c] );
    printf( "\n" );
}
 
/* Converts digit characters into a number until a nondigit is received */
int getnum()
{
    int ch, num =  0;
 
    while( isdigit( ch = _getch() ) )
    {
        _putch( ch );                       /* Display digit     */
        num = (num * 10) + ch  - '0';       /* Convert to number */
    }
    _ungetch( ch );                         /* Put nondigit back */
    return num;                             /* Return result     */
}
 
/* Throws away nondigit characters */
void skiptodigit()
{
    int ch;
 
    while( !isdigit( ch = _getch() ) )
        ;
    _ungetch( ch );
}
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