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Hi everybody,

I got a code (calculate math expression) from a website and I want to use it in my program.

Part of the code:

"

cout << "Don't forget add ';' to the tail of the expression:)" <<endl;

do

{

cin >> temp;

if(isdigit(temp))

{

cin.putback(temp);

cin >> number[ntop++];

}

...............

}

while(temp!=END);

cout << "And the answer is... " << number[0] <<endl;

return 0;

}

"

In my program I already have an expression (char array) so I don't want to use the "cin" commands (especialy cin.putback) to deal with the expression..

I want to use my array or maybe put the string into cin streaming function(if possible) so I'll can use this code..

Any ideas..?

Thanks for your help.

I got a code (calculate math expression) from a website and I want to use it in my program.

Part of the code:

"

cout << "Don't forget add ';' to the tail of the expression:)" <<endl;

do

{

cin >> temp;

if(isdigit(temp))

{

cin.putback(temp);

cin >> number[ntop++];

}

...............

}

while(temp!=END);

cout << "And the answer is... " << number[0] <<endl;

return 0;

}

"

In my program I already have an expression (char array) so I don't want to use the "cin" commands (especialy cin.putback) to deal with the expression..

I want to use my array or maybe put the string into cin streaming function(if possible) so I'll can use this code..

Any ideas..?

Thanks for your help.

1 Solution

Would this be helpful:

for(int i=0;...) {

number[i] = atoi(yourCharArr[i]; //for int atof for double

}

Now you have numbers instead of characters if that was what you tried to achieve

I will leave the following recommendation for this question in the Cleanup Zone:

Accept: UrosVidojevic {http:#18013113}

Any objections should be posted here in the next 4 days. After that time, the question will be closed.

Sean Durkin

Experts Exchange Cleanup Volunteer

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this is sample code that will solve your problem.

The idea is similar to that, you used in your code.

Program is goint through array of chars and checking

for arrays of successive digits (numbers) and puting

them in an array of numbers. At the end program prints

the first of them.

Althought, I don't understand why first of them

should be answer. :-)

Sample code:

=============

__________________________

#include <iostream>

#include <cstring>

using namespace std;

const int MAX_LEN = 1000, // Maximal char array length

MAX_NUM = 500; // Maxinal number of numbers in array

int main() {

char text[MAX_LEN];

cout << "Char array: ";

cin.getline(text, MAX_LEN);

// text is array of characters that you allready have.

// so this is part of code that is particulary

// interesting for your problem.

int i = 0, len = strlen(text), number[MAX_NUM], ntop = 0;

while (true) {

while (i < len && !isdigit(text[i]))

i++;

if (i == len) break;

long num = 0;

while (i < len && isdigit(text[i])) {

num = 10*num + (text[i] - '0');

i++;

}

number[ntop++] = num;

}

// i is index of current character in array

// len is length of array

// number is array if numbers found in array

// num is current number

// ntop is index of current number

cout << "And the answer is: " << number[0] << endl;

// note that if there is no numbers in array

// number[0] will be some random number.

// this is is optional, just to show you

// that program is correct.

cout << "Other numbers: ";

for (int i = 1; i < ntop; i++)

cout << number [i] << " ";

cout << endl;

}

__________________________

Sample input\output 1:

=======================

__________________________

Char array: f(123) + g(12) - sin(45)/tg(32) + 123*456

And the answer is: 123

Other numbers: 12 45 32 123 456

__________________________

Sample input\output 2:

=======================

__________________________

Char array: a(1+b(2+c(3)+2)+1)

And the answer is: 1

Other numbers: 2 3 2 1

__________________________

If I was not clear enough,

I would be glad to help.

Regards, Uros.