Python vs C：不同的输出

Question

我有一个小程序，可以将以10为底的数字转换为以36为底的数字。这是Python代码，它可以按预期工作。

def numToKey(num):

    start = 0x04;

    i = 0;

    for i in range(0,num):

        start+=1

    return start;

def largeNumToKeyboard(num):

    a = num / 1296;

    ar = num % 1296;

    b = ar / 36;

    c = ar % 36;

    a = numToKey(a);

    b = numToKey(b);

    c = numToKey(c);

    newb = b;

    if(a == b):

        newb = 0x2D;

    if(c == b):

        c = 0x2E;

    print a,newb,c

    print

largeNumToKeyboard(0)

largeNumToKeyboard(200)

输出是

4 45 46

4 9 24

“ 4 45 46”正确表示0，而“ 4 9 24”正确表示200。

但是问题是，在将其转换为C代码后，它停止工作。

#include <stdio.h>

int main(int argc, char **argv)

{

    printf("hello world\n");

    largeNumToKeyboard(0);

    largeNumToKeyboard(200);

    return 0;

}

char numToKey(char num) {

    char start = 0x04;

    char i = 0;

    for (i = 0; i < num; i++) {

        start++;

    }

    return start;

}

void largeNumToKeyboard(int num) {

    char a = num / 1296;

    char ar = num % 1296;

    char b = ar / 36;

    char c = ar % 36;

    a = numToKey(a);

    b = numToKey(b);

    c = numToKey(c);

    char newb = b;

    if(a == b){

        newb = 0x2D;

    }

    if(c == b){

        c = 0x2E;

    }

    printf("%d ",a);

    printf("%d ",newb);

    printf("%d\r\n",c);

}

现在的输出是

4 45 46

4 45 46

我不明白为什么对于200的输入，C代码给我错误的输出，但是python代码给我正确的输出。我感觉它与模数有关，但我无法弄清楚。请帮忙！谢谢！

Answer 1

问题是您char在void largeNumToKeyboard(int num)函数中使用了类型，而正在测试的值可能会导致溢出char。您至少需要将前三个更改为int...void largeNumToKeyboard(int num) {&nbsp; &nbsp; int a = num / 1296;&nbsp; &nbsp; int ar = num % 1296;&nbsp; &nbsp; int b = ar / 36;&nbsp; &nbsp; char c = ar % 36;&nbsp; &nbsp; a = numToKey(a);&nbsp; &nbsp; b = numToKey(b);&nbsp; &nbsp; c = numToKey(c);&nbsp; &nbsp; char newb = b;&nbsp; &nbsp; if(a == b){&nbsp; &nbsp; &nbsp; &nbsp; newb = 0x2D;&nbsp; &nbsp; }&nbsp; &nbsp; if(c == b){&nbsp; &nbsp; &nbsp; &nbsp; c = 0x2E;&nbsp; &nbsp; }&nbsp; &nbsp; printf("%d ",a);&nbsp; &nbsp; printf("%d ",newb);&nbsp; &nbsp; printf("%d\r\n",c);}...然后打印输出...4 45 464 9 24