適用於正整數

inline void scan_d(int &ret) 
{
    char c; 
    ret = 0;
    while ((c = getchar()) < '0' || c > '9');
    while (c >= '0' && c <= '9')
    { 
        ret = ret * 10 + (c - '0'), c = getchar();
    }
}

適用於正負整數

inline bool scan_d(int &ret) 
{
    char c; 
    int sgn;
    if (c = getchar(), c == EOF) 
    {
        return 0; //EOF 
    }
    while (c != '-' && (c < '0' || c > '9')) 
    {
        c = getchar(); 
    }
    sgn = (c == '-') ? -1 : 1;
    ret = (c == '-') ? 0 : (c - '0'); 
    while (c = getchar(), c >= '0' && c <= '9') 
    {
        ret = ret * 10 + (c - '0'); 
    }
    ret *= sgn;
    return 1;
}


inline void print_d(int x) 
{ 
    if (x > 9) 
    {
        print_d(x / 10); 
    }
    putchar(x % 10 + '0');
}
 

僅適合純數字輸入輸出

int Scan()
{   //  輸入外掛  
    int res = 0, flag = 0;  
    char ch;  
    if ((ch = getchar()) == '-') 
    {   
        flag = 1;  
    }    
    else if(ch >= '0' && ch <= '9') 
    {
        res = ch - '0'; 
    }
    while ((ch = getchar()) >= '0' && ch <= '9')  
    {
        res = res * 10 + (ch - '0');  
    }
    return flag ? -res : res;  
}  

void Out(int a) 
{   //  輸出外掛  
    if (a < 0) 
    {
        putchar('-');
        a = -a;
    }  
    if (a >= 10)
    {
       Out(a / 10);  
    }
    putchar(a % 10 + '0');  
}  

int main() 
{  
    int T, n;  
    scanf ("%d", &T);  
    while (T--) 
    {  
        n = Scan();  
        Out(n);  
        printf("\n");  
    }  
    return 0;  
}
 

適用於正負數(int,long long,float,double)

bool scan_d(T &ret)
{
    char c; 
    int sgn; 
    T bit = 0.1;
    if (c=getchar(), c==EOF) 
    {
        return 0;
    }
    while (c! = '-' && c != '.' && (c < '0' || c > '9')) 
    {
        c = getchar();
    }
    sgn = (c == '-') ? -1 : 1;
    ret = (c == '-') ? 0 : (c - '0');
    while (c = getchar(), c >= '0' && c <= '9')
    {
        ret = ret * 10 + (c - '0');
    }
    if (c == ' ' || c == '\n')
    {
        ret *= sgn;
        return 1;
    }
    while (c = getchar(), c >= '0' && c <= '9')
    {
        ret += (c - '0') * bit, bit /= 10;
    }
    ret *= sgn;
    return 1;
}


inline void print_d(int x)
{
    if (x > 9)
    {
        print_d(x / 10);
    }
    putchar(x % 10 + '0');
}
 

其他

上面那個輸入正負整數的有點難用。
再附一個：

void in(int &m)
{
    char ch;
    int flag = 0;
    while ((ch = getchar()) < '0' || ch > '9')
    {
        if (ch == '-')
        {
            flag = 1;
        }
    }
    for (m = 0; ch >= '0' && ch <= '9'; ch = getchar())
    {
        m = m * 10 + ch - '0';
    }
    if (flag)
    {
        m *= -1;
    }
}