使用fscanf扫描+或 - 类型符号

Question

如果我正在检查fscanf或'+'或'-'等，我会在'%'中测试什么。

例如，如果我正在测试int，我会这样做：

    if(fscanf(read,"%d", &d)) //do something
    else if (fscanf(read,"%s", s)) // do something else
    else if fscanf(read,"%?", ?) //case for + - % /

相关代码：

while(feof(read) == 0){


    //printf("help me");
    if(fscanf(read,"%d", &d)) {
        /* this makes sure that ints preceding "pick" etc are not
         * counted as ints that are pushed onto the stack. Further this makes sure
         * the testing for this does not "eat" and of the words in the file
         */ 

        //if (d == '+') {
            //fprintf (write, "\t+ DETECTED\n");
        //}
        const long pos = ftell(read); // stores current position
        //checks if the next thing 
        if (fscanf(read,"%s", s)){
            if ((strcmp(s , "pick") == 0 || (strcmp(s , "eq") == 0))){
                //fprintf (write, "%d %s called\n", d, s);
            }
            else {
                push(d, write);
                //undo the word we "ate" 
                fseek(read, pos, SEEK_SET);
            }
        } else push(d, write);
    } 

    else if (fscanf(read,"%s", s)){ 
        if (strcmp(s , "defun") == 0) {
            fscanf(read,"%s", s);
            printdefun (s, write);
        }
        else if (strcmp(s , "return") == 0) {
            printreturn (write);
        }
        else if (strcmp(s , "return") == 0) {
            fprintf (write, "\t+ detected\n");
        }
    }
    else if (fscanf(read,"%c", &c)){ 
        if (c == '+') {
            fprintf (write, "\t+ DETECTED\n");
        }
    }

文本文件：

    defun main
15 10 +
return

请注意，“+ detected”永远不会被打印