c - 如何使用 regex.h 查找美元符号

Question

下面是我的代码，我想在其中查找字符串是否包含 $ 符号，但它显示错误:error: unknown escape sequence '\$'

#include <sys/types.h>
#include <regex.h>
#include <stdio.h>

#define MAX_MATCHES 1 //The maximum number of matches allowed in a single string

void match(regex_t *pexp, char *sz) {
        regmatch_t matches[MAX_MATCHES]; //A list of the matches in the string (a list of 1)
        //Compare the string to the expression
        //regexec() returns 0 on match, otherwise REG_NOMATCH
        if (regexec(pexp, sz, MAX_MATCHES, matches, 0) == 0) {
                printf(" matches characters ");
        } else {
                printf(" does not match\n");
        }
}

int main() {
        int rv;
        regex_t exp; //Our compiled expression
        //1. Compile our expression.
        //Our regex is "-?[0-9]+(\\.[0-9]+)?". I will explain this later.
        //REG_EXTENDED is so that we can use Extended regular expressions
        rv = regcomp(&exp, "\$", REG_EXTENDED);
        if (rv != 0) {
                printf("regcomp failed with %d\n", rv);
        }
        //2. Now run some tests on it
        match(&exp, "Price of iphone is $800 ");

        //3. Free it
        regfree(&exp);
        return 0;
}

Answer 1

您需要转义反斜杠:

rv = regcomp(&exp, "\\$", REG_EXTENDED);