检查文本文件中的新行

Question

我正在试着写一段代码，它能从文件中读取数据，并能处理所读取的字符。要点是它必须纠正它读取的文件中存在的大小写错误。

一个特殊的要求是我必须对每一行进行编号，所以我编写了一些代码来确定读取的每个字符是否是换行符。

int fix_caps(char* ch, int* char_in_word, int* line_num){

char a;
ch = &a;

if(a != '\n'){
    return 0;
}else{
    return 1;
}

if(a == ' ')
   *char_in_word = 0;

if(*char_in_word == 1)
   a = toupper(a);

if(*char_in_word > 1)
   a = tolower(a);

char_in_word++;

}

然而，this所在的函数总是返回0，而它应该在每行的末尾返回1。我做错了什么？

Answer 1

the execution will never get beyond this 'if control block:

char a;
ch = &a;

if(a != '\n'){
   return 0;
}else{
    return 1;
}

there is a few reasons it 'always' returns 0
1) 'a' is on the stack and could contain anything.
2) the chances of the 'trash' that is on the stack where 'a'
   is located are 255:1 against the trash happening to contain
   a new line character.

nothing beyond the 'if control block is ever executed because
an 'if' control block only has two execution paths 
and both paths contain a return statement.