Test_C/1.9.txt

#include <stdio.h>

int main()
{
    int c;
    int ws = 0;
    
    while ((c = getchar()) != EOF)
    {
        if (c == ' ')
        {
            ++ws;
            if (ws < 2)
                printf("%c", c);
        }
        else
        {
            printf("%c", c);
            ws = 0;
        }
    }

    return 0;
}