記號化的字符串在C++

Question

我有形式的字符串

ADD，R1，＃分隔值5

我想將其轉換爲三個獨立的變量

string s1 =「ADD」;

int register = 1; [刪除'R'並轉換爲int後]

int literal = 5; [刪除＃並轉換成int後]

我試着將它轉換成char *使用strok（）函數，但輸出似乎並不緊張

Answer 1

你想要寫一個解析器。爲了讓我的答案簡單而簡短，我爲你寫了一個非常簡單的解析器。這裏是：

// Written by 'imerso' for a StackOverflow answer 

#include <string.h> 
#include <stdio.h> 
#include <stdlib.h> 


// Extract next substring from current pointer 
// to next separator or end of string 
char* NextToken(char** cmd, const char* sep) 
{ 
    char* pStart = *cmd; 
    char* pPos = strstr(*cmd, sep); 

    if (!pPos) 
    { 
     // no more separators, return the entire string 
     return *cmd; 
    } 

    // return from the start of the string up to the separator 
    *pPos = 0; 
    *cmd = pPos+1; 
    return pStart; 
} 


// Warning: this is a very simple and minimal parser, meant only as an example, 
// so be careful. It only parses the simple commands without any spaces etc. 
// I suggest you to try with ADD,R1,#5 similar commands only. 
// A full parser *can* be created from here, but I wanted to keep it really simple 
// for the answer to be short. 
int main(int argc, char* argv[]) 
{ 
    // requires the command as a parameter 
    if (argc != 2) 
    { 
     printf("Syntax: %s ADD,R1,#5\n", argv[0]); 
     return -1; 
    } 

    // the command will be split into these 
    char token[32]; 
    int reg = 0; 
    int lit = 0; 

    // create a modificable copy of the command-line 
    char cmd[64]; 
    strncpy(cmd, argv[1], 64); 
    printf("Command-Line: %s\n", cmd); 

    // scan the three command-parameters 
    char* pPos = cmd; 
    strncpy(token, NextToken(&pPos, ","), 32); 
    reg = atoi(NextToken(&pPos, ",")+1); 
    lit = atoi(NextToken(&pPos, ",")+1); 

    // show 
    printf("Command: %s, register: %u, literal: %u\n", token, reg, lit); 

    // done. 
    return 0; 
}