c语言输入输出优化

#include<cctype> //为了使用isdigit宏

inline int readint() {
char c = getchar();
while(!isdigit(c)) c = getchar();
int x = 0;
while(isdigit(c)) {
x = x * 10 + c - '0';
c = getchar();
}
return x;
}
int buf[10];
inline void writeint(int i) {
int p = 0;
if(i == 0) p++;
else while(i) {
buf[p++] = i % 10;
i /= 10;
}
for(int j = p-1; j >= 0; j--) putchar('0' + buf[j]);
}