/in/lab4.c: In function 'storevar':
/in/lab4.c:25:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<strlen(ch);i++){
                  ^
/in/lab4.c: In function 'calculate':
/in/lab4.c:126:23: warning: value computed is not used [-Wunused-value]
                 stack1[top1--];
                 ~~~~~~^~~~~~~~
/in/lab4.c: In function 'strrpl':
/in/lab4.c:194:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     while (ptr = strstr(s, s1)) // 如果在s中找到s1
            ^~~
/in/lab4.c: In function 'syntax':
/in/lab4.c:228:31: warning: passing argument 3 of 'findvars' makes integer from pointer without a cast [-Wint-conversion]
     else if(findvars(vars,str,varnums)!=-1 && strstr(str, "fprintf") == NULL&& strstr(str, "=") == NULL)
                               ^~~~~~~
/in/lab4.c:215:5: note: expected 'int' but argument is of type 'int *'
 int findvars(char vars[20][15],char ch[15],int varnums){
     ^~~~~~~~
/in/lab4.c:320:21: warning: array subscript is above array bounds [-Warray-bounds]
             nextline[4] = 0;
             ~~~~~~~~^~~
In file included from /usr/include/stdio.h:862:0,
                 from /in/lab4.c:1:
In function 'fgets',
    inlined from 'main' at /in/lab4.c:356:16:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:260:9: warning: call to '__fgets_chk_warn' declared with attribute warning: fgets called with bigger size than length of destination buffer
  return __fgets_chk_warn (__s, __bos (__s), __n, __stream);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~