就是用getchar();
int read_In() {
int a = 0;
bool minus = false;
char ch = getchar();
while (!(ch == '-' || (ch >= '0' && ch <= '9'))) ch = getchar();
if (ch == '-') {
minus = true;
ch = getchar();
}
while (ch >= '0' && ch <= '9') {
a = a * 10 + (ch - '0');
ch = getchar();
}
if (minus) a = -a;
return a;
}
void printOut(int x) {
char buffer[20];
int length = 0;
bool minus = x < 0;
if (minus) x = -x;
do {
buffer[length++] = x % 10 + '0';
x /= 10;
} while (x);
if (minus) buffer[length++] = '-';
do {
putchar(buffer[--length]);
} while (length);
putchar('\n');
}