问题描述
我在拆分字符串时遇到问题.下面的代码有效,但前提是字符串之间是 ' '(空格).但是即使有任何 whitespace 字符,我也需要拆分字符串.strtok()
甚至是必要的吗?
I have problem with splitting a string. The code below works, but only if between strings are ' ' (spaces). But I need to split strings even if there is any whitespace char. Is strtok()
even necessary?
char input[1024];
char *string[3];
int i=0;
fgets(input,1024,stdin)!='\0') //get input
{
string[0]=strtok(input," "); //parce first string
while(string[i]!=NULL) //parce others
{
printf("string [%d]=%s\n",i,string[i]);
i++;
string[i]=strtok(NULL," ");
}
推荐答案
一个简单的示例,展示了如何在代码中使用多个分隔符和潜在的改进.请参阅嵌入的注释以获取解释.
A simple example that shows how to use multiple delimiters and potential improvements in your code. See embedded comments for explanation.
请注意 strtok()
的一般缺点(来自手册):
Be warned about the general shortcomings of strtok()
(from manual):
这些函数修改它们的第一个参数.
这些函数不能用于常量字符串.
These functions cannot be used on constant strings.
分隔字节的标识丢失.
strtok()
函数在解析时使用静态缓冲区,所以它不是线程安全的.如果这对您很重要,请使用 strtok_r()
.
The strtok()
function uses a static buffer while parsing, so it's not thread safe. Use strtok_r()
if this matters to you.
#include <stdio.h>
#include<string.h>
int main(void)
{
char input[1024];
char *string[256]; // 1) 3 is dangerously small,256 can hold a while;-)
// You may want to dynamically allocate the pointers
// in a general, robust case.
char delimit[]=" \t\r\n\v\f"; // 2) POSIX whitespace characters
int i = 0, j = 0;
if(fgets(input, sizeof input, stdin)) // 3) fgets() returns NULL on error.
// 4) Better practice to use sizeof
// input rather hard-coding size
{
string[i]=strtok(input,delimit); // 5) Make use of i to be explicit
while(string[i]!=NULL)
{
printf("string [%d]=%s\n",i,string[i]);
i++;
string[i]=strtok(NULL,delimit);
}
for (j=0;j<i;j++)
printf("%s", string[i]);
}
return 0;
}
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