函数没有收到我作为 const char * 发送的内容
Function is not receiving what I send as a const char *
static char DEFAULT_DELIMITER = ',';
char *calculator_retrieveFirstToken(char *numbers, const char * delimiters) {
//if (delimiters[strlen(delimiters)-1] == DEFAULT_DELIMITER)
if (delimiters[1] == DEFAULT_DELIMITER) {
return strtok(numbers, delimiters);
}
else {
char linefeed = '\n';
strtok(numbers, &linefeed);
return strtok(NULL, delimiters);
}
}
char calculator_findDelimiter(const char *numbers) {
char delimiter = DEFAULT_DELIMITER;
if (strlen(numbers) >= 4
&& numbers[0] == '/'
&& numbers[1] == '/') {
delimiter = numbers[2];
}
return delimiter;
}
double calculator_add(char *numbers) {
char delimiters[] = "\n";
char *token = NULL;
char mainDelimiter = calculator_findDelimiter(numbers);
strcat(delimiters, &mainDelimiter);
token = calculator_retrieveFirstToken(numbers, delimiters);
return calculator_addEveryToken(token, delimiters);
}
最奇怪的事情发生在我调试 calculator_retrieveFirstToken 函数时。
数字输入示例:“”
mainDelimiter 等于','
调用 strcat 后:定界符等于:"\n,"
当我进入 calculator_retrieveFirstToken 函数时,分隔符参数等于:
"\n,\n,"
我不明白这是怎么回事....我的 strcat 调用有问题吗?
这是主要内容
#include "calculator_kata.h"
#include <assert.h>
#include <string.h>
#include <math.h>
#include <stdbool.h>
static char numbers[50];
static bool equals(const double expected, const double received)
{
double epsilon = 1e-7;
return fabs(received - expected) < epsilon;
}
static void test_addEmptyString_shouldReturnZero()
{
strcpy(numbers, "");
const double sum = calculator_add(numbers);
assert(equals(0, sum));
}
static void test_addOneNumber_shouldReturnThisNumber()
{
strcpy(numbers, "42");
const double sum = calculator_add(numbers);
assert(equals(42, sum));
}
static void test_addTwoNumbers_shouldReturnTheSum()
{
const double TWENTY_ONE = 9+10;
strcpy(numbers, "9,10");
const double sum = calculator_add(numbers);
assert(equals(TWENTY_ONE, sum));
}
static void test_addAnyQtyOfNumbers_shouldReturnTheSum()
{
strcpy(numbers, "1,2,3,4,5");
const double sum = calculator_add(numbers);
assert(equals(15, sum));
}
static void test_inputWithNewLines_insteadOfCommas_shouldStillBeParsed()
{
strcpy(numbers, "1\n2,3");
const double sum = calculator_add(numbers);
assert(equals(6, sum));
}
static void test_inputWithMultipleCommasBetweenNumbers_shouldReturnTheSum()
{
strcpy(numbers, "1\n,2,,,,,,,3");
const double sum = calculator_add(numbers);
assert(equals(6, sum));
}
static void test_inputWithCustomDelimiter_shouldChangeDelimiter()
{
strcpy(numbers, "//;\n1;2");
const double sum = calculator_add(numbers);
assert(equals(3, sum));
}
int main()
{
test_addEmptyString_shouldReturnZero();
test_addOneNumber_shouldReturnThisNumber();
test_addTwoNumbers_shouldReturnTheSum();
test_addAnyQtyOfNumbers_shouldReturnTheSum();
test_inputWithNewLines_insteadOfCommas_shouldStillBeParsed();
test_inputWithMultipleCommasBetweenNumbers_shouldReturnTheSum();
test_inputWithCustomDelimiter_shouldChangeDelimiter();
return 0;
}
strtok
和 strcat
接受指向 char
数组(即字符串)的指针,而 而不是 指向 char
多变的。也就是说,他们需要字符串终止符 ('[=15=]'
).
此外,在 calculator_add
中,您没有在 delimiters
中定义足够的 space,因此您的 strcat
会 运行 超过结尾,导致未定义的行为。
我已经用错误注释了您的来源并提供了修复。在可能的情况下,我已经完成了:// NOTE/BUG: ... #if 0 /* original code */ #else /* fixed code */ #endif
:
static char DEFAULT_DELIMITER = ',';
char *calculator_retrieveFirstToken(char *numbers, const char * delimiters) {
//if (delimiters[strlen(delimiters)-1] == DEFAULT_DELIMITER)
if (delimiters[1] == DEFAULT_DELIMITER) {
return strtok(numbers, delimiters);
}
else {
// NOTE/BUG: this is incorrect -- you must pass a string pointer _not_
// the address of a [single] character
#if 0
char linefeed = '\n';
strtok(numbers, &linefeed);
#else
char *linefeed = "\n";
strtok(numbers, linefeed);
#endif
return strtok(NULL, delimiters);
}
}
char calculator_findDelimiter(const char *numbers) {
char delimiter = DEFAULT_DELIMITER;
if (strlen(numbers) >= 4
&& numbers[0] == '/'
&& numbers[1] == '/') {
delimiter = numbers[2];
}
return delimiter;
}
double calculator_add(char *numbers) {
// NOTE/BUG: this defines only enough space for a single character and the
// '[=10=]' so when it is concatenated to, it is undefined behavior [you're
// running past the end of the string]
#if 0
char delimiters[] = "\n";
#else
char delimiters[4] = "\n";
#endif
char *token = NULL;
// NOTE/BUG: this repeats the same mistake with the strtok above
#if 0
char mainDelimiter = calculator_findDelimiter(numbers);
strcat(delimiters, &mainDelimiter);
#endif
// NOTE: either of these will fix the strcat
#if 0
char mainDelimiter = calculator_findDelimiter(numbers);
char temp[2];
temp[0] = mainDelimiter;
temp[1] = 0;
strcat(delimiters, temp);
#else
delimiters[1] = calculator_findDelimiter(numbers);
delimiters[2] = 0;
#endif
token = calculator_retrieveFirstToken(numbers, delimiters);
return calculator_addEveryToken(token, delimiters);
}
static char DEFAULT_DELIMITER = ',';
char *calculator_retrieveFirstToken(char *numbers, const char * delimiters) {
//if (delimiters[strlen(delimiters)-1] == DEFAULT_DELIMITER)
if (delimiters[1] == DEFAULT_DELIMITER) {
return strtok(numbers, delimiters);
}
else {
char linefeed = '\n';
strtok(numbers, &linefeed);
return strtok(NULL, delimiters);
}
}
char calculator_findDelimiter(const char *numbers) {
char delimiter = DEFAULT_DELIMITER;
if (strlen(numbers) >= 4
&& numbers[0] == '/'
&& numbers[1] == '/') {
delimiter = numbers[2];
}
return delimiter;
}
double calculator_add(char *numbers) {
char delimiters[] = "\n";
char *token = NULL;
char mainDelimiter = calculator_findDelimiter(numbers);
strcat(delimiters, &mainDelimiter);
token = calculator_retrieveFirstToken(numbers, delimiters);
return calculator_addEveryToken(token, delimiters);
}
最奇怪的事情发生在我调试 calculator_retrieveFirstToken 函数时。
数字输入示例:“”
mainDelimiter 等于','
调用 strcat 后:定界符等于:"\n,"
当我进入 calculator_retrieveFirstToken 函数时,分隔符参数等于: "\n,\n,"
我不明白这是怎么回事....我的 strcat 调用有问题吗?
这是主要内容
#include "calculator_kata.h"
#include <assert.h>
#include <string.h>
#include <math.h>
#include <stdbool.h>
static char numbers[50];
static bool equals(const double expected, const double received)
{
double epsilon = 1e-7;
return fabs(received - expected) < epsilon;
}
static void test_addEmptyString_shouldReturnZero()
{
strcpy(numbers, "");
const double sum = calculator_add(numbers);
assert(equals(0, sum));
}
static void test_addOneNumber_shouldReturnThisNumber()
{
strcpy(numbers, "42");
const double sum = calculator_add(numbers);
assert(equals(42, sum));
}
static void test_addTwoNumbers_shouldReturnTheSum()
{
const double TWENTY_ONE = 9+10;
strcpy(numbers, "9,10");
const double sum = calculator_add(numbers);
assert(equals(TWENTY_ONE, sum));
}
static void test_addAnyQtyOfNumbers_shouldReturnTheSum()
{
strcpy(numbers, "1,2,3,4,5");
const double sum = calculator_add(numbers);
assert(equals(15, sum));
}
static void test_inputWithNewLines_insteadOfCommas_shouldStillBeParsed()
{
strcpy(numbers, "1\n2,3");
const double sum = calculator_add(numbers);
assert(equals(6, sum));
}
static void test_inputWithMultipleCommasBetweenNumbers_shouldReturnTheSum()
{
strcpy(numbers, "1\n,2,,,,,,,3");
const double sum = calculator_add(numbers);
assert(equals(6, sum));
}
static void test_inputWithCustomDelimiter_shouldChangeDelimiter()
{
strcpy(numbers, "//;\n1;2");
const double sum = calculator_add(numbers);
assert(equals(3, sum));
}
int main()
{
test_addEmptyString_shouldReturnZero();
test_addOneNumber_shouldReturnThisNumber();
test_addTwoNumbers_shouldReturnTheSum();
test_addAnyQtyOfNumbers_shouldReturnTheSum();
test_inputWithNewLines_insteadOfCommas_shouldStillBeParsed();
test_inputWithMultipleCommasBetweenNumbers_shouldReturnTheSum();
test_inputWithCustomDelimiter_shouldChangeDelimiter();
return 0;
}
strtok
和 strcat
接受指向 char
数组(即字符串)的指针,而 而不是 指向 char
多变的。也就是说,他们需要字符串终止符 ('[=15=]'
).
此外,在 calculator_add
中,您没有在 delimiters
中定义足够的 space,因此您的 strcat
会 运行 超过结尾,导致未定义的行为。
我已经用错误注释了您的来源并提供了修复。在可能的情况下,我已经完成了:// NOTE/BUG: ... #if 0 /* original code */ #else /* fixed code */ #endif
:
static char DEFAULT_DELIMITER = ',';
char *calculator_retrieveFirstToken(char *numbers, const char * delimiters) {
//if (delimiters[strlen(delimiters)-1] == DEFAULT_DELIMITER)
if (delimiters[1] == DEFAULT_DELIMITER) {
return strtok(numbers, delimiters);
}
else {
// NOTE/BUG: this is incorrect -- you must pass a string pointer _not_
// the address of a [single] character
#if 0
char linefeed = '\n';
strtok(numbers, &linefeed);
#else
char *linefeed = "\n";
strtok(numbers, linefeed);
#endif
return strtok(NULL, delimiters);
}
}
char calculator_findDelimiter(const char *numbers) {
char delimiter = DEFAULT_DELIMITER;
if (strlen(numbers) >= 4
&& numbers[0] == '/'
&& numbers[1] == '/') {
delimiter = numbers[2];
}
return delimiter;
}
double calculator_add(char *numbers) {
// NOTE/BUG: this defines only enough space for a single character and the
// '[=10=]' so when it is concatenated to, it is undefined behavior [you're
// running past the end of the string]
#if 0
char delimiters[] = "\n";
#else
char delimiters[4] = "\n";
#endif
char *token = NULL;
// NOTE/BUG: this repeats the same mistake with the strtok above
#if 0
char mainDelimiter = calculator_findDelimiter(numbers);
strcat(delimiters, &mainDelimiter);
#endif
// NOTE: either of these will fix the strcat
#if 0
char mainDelimiter = calculator_findDelimiter(numbers);
char temp[2];
temp[0] = mainDelimiter;
temp[1] = 0;
strcat(delimiters, temp);
#else
delimiters[1] = calculator_findDelimiter(numbers);
delimiters[2] = 0;
#endif
token = calculator_retrieveFirstToken(numbers, delimiters);
return calculator_addEveryToken(token, delimiters);
}