Question

我正在处理一个函数，该函数接受一个字符串参数（实际上从主函数发送一个char数组，但不要认为这有所不同）在C中，并解析要存储在链接中的字符串列表（这是学校的作业），我收到了分段错误。我已经在整个程序中添加了要打印的字符串以调试程序，因为它依赖于输入文件，我不知道如何使用输入选项启动gdb。

这就是我的功能：

Token * list_head = NULL;
    Token * current = NULL;
    char line_segment[MAX_PRINT_LINE_LENGTH + 1];
    int i, pos = 0; //In the for loop, we do not not to lose the pos in the array
    puts("in token.c, beginning segmentation");

    /***************************************************************************
     * Loop through the possibilites of the first character starting at the 
     * position located at the pointer (pretty sure this is still easier on the
     * memory and logically then enumerating all of the different symbols and 
     * types of chars that you will see.
     **************************************************************************/
    for(i=0; line_copy[pos] != '\0';){
            if(line_copy[pos] == 'a' || 'b' || 'c' || 'd' || 'e' || 'f' || 'g' ||
                                 'h' || 'i' || 'j' || 'k' || 'l' || 'm' || 'n' ||
                                 'o' || 'p' || 'q' || 'r' || 's' || 't' || 'u' ||
                                 'v' || 'w' || 'x' || 'y' || 'z' || 'A' || 'B' ||
                                 'C' || 'D' || 'E' || 'F' || 'G' || 'H' || 'I' ||
                                 'J' || 'K' || 'L' || 'M' || 'N' || 'O' || 'P' ||
                                 'Q' || 'R' || 'S' || 'T' || 'U' || 'V' || 'W' ||
                                 'X' || 'Y' || 'Z') //Identifier or Rw
                    do{
                            line_segment[i] = line_copy[pos];
                            pos++; i++;
                    } while(line_copy[pos] == //All letters of alphabet);
            else if(line_copy[pos] == '0' || '1' || '2' || '3' || '4' || '5' ||
                                      '6' || '7' || '8' || '9'){ //Number
                    do{
                            line_segment[i] = line_copy[pos];
                            pos++; i++;
                    } while(line_copy[pos] == '0' || '1' || '2' || '3' || '4' || '5' ||
                                              '6' || '7' || '8' || '9' || 'e');
            }
            else if(line_copy[pos] == " "){ //No token
                    line_segment[i] = '\0';
                    pos++;
            }
            else if(line_copy[pos] == "'"){ //String
                    do{ //We want to keep the first apostrophe for make_node
                            line_segment[i] = line_copy[pos];
                            pos++; i++;
                    } while(line_copy[pos] != "'");
                    pos++; //Don't want to start on the ending ' symbol.
            }
            else{ //Symbol
                    line_segment[i] = line_copy[pos];
                    pos++;
            }
            puts("line segmented, attempting node");
            printf("line segment: %s\n", line_segment);
            current = make_node(line_segment);
            memset(line_segment, '\0', MAX_PRINT_LINE_LENGTH);
            puts("attempting to add node to list");
            list_head = add_to_list(list_head, current);
            free(current);
            puts("node freed");
    }
    return list_head;
}

Answer 1

        if(line_copy[pos] == 'a' || 'b' || 'c' || 'd' || 'e' || 'f' || 'g' ||
                             'h' || 'i' || 'j' || 'k' || 'l' || 'm' || 'n' ||
                             'o' || 'p' || 'q' || 'r' || 's' || 't' || 'u' ||
                             'v' || 'w' || 'x' || 'y' || 'z' || 'A' || 'B' ||
                             'C' || 'D' || 'E' || 'F' || 'G' || 'H' || 'I' ||
                             'J' || 'K' || 'L' || 'M' || 'N' || 'O' || 'P' ||
                             'Q' || 'R' || 'S' || 'T' || 'U' || 'V' || 'W' ||
                             'X' || 'Y' || 'Z')

您必须遵循实际的C语法。你无法做到并期望它们发挥作用。你正在对一堆字母进行ORing，这没有任何意义。

Answer 2

尝试使用ctype.h中的isalpha()和isdigit()函数。

解析Char数组时的分段错误

2 个答案: