整型数据与字符串类型相互转化的一种实现方法

浅浅的花香味﹌ 2022-08-06 06:28 199阅读 0赞

void itoa(char * buffer, int num, int length)
{
    int i = 0;
    int temp = num;
    if (temp == 0)
    {
        for (i = 0; i < length; i++)
        {
            buffer[i] = '0';
        }
        buffer[i] = 0;
    }
    else
    {
        if (temp < 0)
        {
            buffer[0] = '-';
            temp = -temp;
            ++i;
        }
        else
            buffer[0] = '0';
        while(temp != 0)
        {
            temp /= 10;
            ++i;
        }
        if (length > i)
            i = length;
        buffer[i] = 0;
        --i;
        temp = num;
        if (temp < 0)
            temp = -temp;
        while(temp != 0)
        {
            buffer[i] = temp % 10 + '0';
            temp /= 10;
            --i;
        }
        while( i >= 0 && buffer[i] != '-')
        {
            buffer[i] = '0';
            --i;
        }
    }
}
#ifndef __stdlib_h
int atoi(char * buffer)
{
    int i;
    int negative = 0;
    int result = 0;
    for (i = 0; buffer[i] == '0'; i++);
    if (buffer[i] == 0)
        return 0;
    else
    {
        if (buffer[i] == '-')
        {
            negative = 1;
            ++i;
        }
        for (; buffer[i]; i++)
        {
            result *= 10;
            result += buffer[i] - '0';
        }
    }
    if (negative)
        result = -result;
    return result;
}