1.输入复制到输出，并将其中连续多个空格用一个空格代替

#include <stdio.h>

#define NONBANK 'a'

int main()
{
int c, lastc;

lastc = NONBLANK;
while ((c = getchar()) != EOF) {
if (c != ' ') {
putchar(c);
}
if (c == ' ') {
if (lastc != ' ') {
putchar(c);
}
}
lastc = c;
}
}