convert

[rootkit]

Hi I have a problem.
This program is something like calculator just x + y. But i dont know how to convert number in int array to char from decimal. I know it can be easy but I must do it this way.

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

void reada(int *a);
int number(int *a);

int length=0;
int m=0;

void reada(int *a)

{
    int b;
    while((b=getchar()) != '\n' && b != EOF && length != 40)
    {
        a[length]=b;
        length++;
        if (length == 40)  printf("end :D \n");
    }

}

int number(int *a)
{
    int b=0;

    while(isdigit(a[m]) && m <= length)
    {
    b = (b*10) + a[m];
    m++;
    }
    return b;
}
int main(void)
{
int a[42]={0};
int *b;
int x;
int y;
 
b=a;    
reada(b);
x = number(b);
m++;
y = number(b);

printf("result is %d \n",x+y);

return 0;
}

[whiteflags]

Well I see the problem.

2
result is 50

You have to remember that the numerical character constants do not correspond to their numerical values. See Ascii Table - ASCII character codes and html, octal, hex and decimal chart conversion for example. So you have to do math, take away the value '0', to store the right values.

[rootkit]

I see but I dont know how to do it in c language. I know ASCII table. The proglem is here : b = (b*10) + a[m]; because a[m] is not number it is char of number for example (chr 5 : dec 53). I need convert 53 to 5.

INPUT:
123+234
OUTPUT:
11013

It is not corret.

[ZuK]

Do as whiteflags has told you
insted of a[m] use a[m]-'0'
Kurt

[rootkit]

Thanks

[rootkit]

And one more think.
What is opposite operation?

[whiteflags]

And one more think.
What is opposite operation?

You mean how to convert to text again. Just add '0' back to the digit.