| re: alternative for pointers
"stanlo" <mungwest@yahoo.com> wrote in message
news:1105307821.732625.54300@c13g2000cwb.googlegro ups.com...[color=blue]
> Hello to all, i have a progam fragment here for the follow up of my
> project ; mathematicl expression. i don t want to use pointers, this is
> the fragment.my problem is there an alternative way of declaring and
> defining my functions without using pointers,eg in the goToOp1
> function, i don t wish to write "char*line".[/color]
If you insist upon using 'C-style' strings, pointers are
the only way to pass them to functions. However the C++
standard library provides a 'string' type (declared by standard
header <string>). Look it up in your C++ textbook.
[color=blue]
> this function gets the first operator in the mathematical expression
> like 1+6*6/2.
>
> //function declarations
>
> int goToOp1(char* line, int startPos, int &curExprBegin);[/color]
int goToOp1(const std::string& line,
std::string::size_type startPos,
int &curExprBegin);
[color=blue]
>
> int goToOp2(char* line, int startPos, int &curExprEnd);[/color]
int goToOp2(const std::string& line,
std::string::size_type startPos,
int &curExprEnd);
[color=blue]
>
> void reduceArr(char* line, int curExprBegin, int curExprEnd, long
> number);[/color]
void reduceArr(const std::string& line,
int curExprBegin,
int curExprEnd,
long number);
BTW why do some of these take references to int, and some
int by value?
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>
> void discardBadChar(char* line, bool &exit);[/color]
void discardBadChar(const std::string& line, bool &exit);
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>
> void errorOutput(const char* erroralert);[/color]
void errorOutput(const std::string& erroralert);
[color=blue]
>
> //function definitons, i did just the definition of one of the
> functions
>
> int goToOp1(char* line, int startPos, int &curExprBegin)[/color]
int goToOp1(const std::string& line,
std::string::size_type startPos,
int &curExprBegin)
[color=blue]
> {
> int pos=startPos-2;[/color]
std::string::size_type pos(startPos-2);
Why subtracting 2?
[color=blue]
>
> int op1Size=0;
>
> int answer;
>
> answer = 0;[/color]
Why not simply:
int answer(0);
Without more context, I cannot comment on whether your
other argument types and return types are appropriate.
-Mike
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