[演算法笔记]字串變整數

#include <stdio.h>
#include <iostream>
using namespace std;

int string_length(char *s)
{
    int n = 0;
    while (s[n]) n++;
    return n;
}

int pow10(int exp)
{
    int n = 1;
    for (int i = 0; i < exp; i++)
        n *= 10;
    return n;
}

void string_to_integer()
{
    char s[10] = "26962869";
    int length =string_length(s);
    
    int n = 0;
    for (int i = 0; i < length; i++)
        n += (s[i] - '0') * pow10(length - 1 - i);

    cout << n;
}

void string_to_integer2()
{
    char s[10] = "26962869";

    int n = 0;
    for (int i = 0; s[i]; i++)
        n = n * 10 + s[i] - '0';

    cout << n;
}