ungetc

函数名: ungetc

功 能: 把一个字符退回到输入流中

用 法: int ungetc(char c, FILE *stream);

输入参数：c 要写入的字符，stream 文件流指针

输出参数：字符c - 操作成功，EOF - 操作失败

程序例:

#include

#include

int main( void )

{

int i=0;

char ch;

puts("Input an integer followed by a char:");

/* read chars until non digit or EOF */

while((ch = getchar()) != EOF && isdigit(ch))

i = 10 * i + ch - 48; /* convert ASCII into int value */

/* if non digit char was read, push it back into input buffer */

if (ch != EOF)

ungetc(ch, stdin);

printf("i = %d, next char in buffer = %c

", i, getchar());

return 0;

}