Question

Suppose I have:

Operand[2][4] = {{"1", "2", "3", "4"},{"5", "6", "7", "8"}};

and I have some bit variables called Operand1_sign and Operand2_sign (0: positive and 1: negative) suppose they are:

Operand1_sign = 0;
Operand2_sign = 1;

How can I convert this into 2 integers and apply some operation on them (such as summation)

i.e.

signed int Operand1, Operand2, Result;

so finally I can get the following:

Operand1 = + 1234;
Operand2 = - 5678;
Result = Operand1 + Operand2;

Answer 1

I could suggest this:

#include <stdio.h>
#include <string.h>

int my_atoi(char* operand, int bufsize, int sign)
{
    char* value = new char[bufsize+1];
    memcpy(value, operand, bufsize);
    value[bufsize] = '\0';
    int ret = 0;
    sscanf(value, "%d", &ret);
    if (sign < 0)
    {
        ret = -ret;
    }
    delete [] value;
    return ret;
}

void main()
{
    char Operand[2][4] = {{'1', '2', '3', '4'},{'5', '6', '7', '8'}};
    signed int Operand1 = my_atoi(Operand[0], 4, 1);
    signed int Operand2 = my_atoi(Operand[1], 4, -1);
    signed int Result = Operand1 + Operand2;
}

However, I would definitely recommend you get your strings as null terminated strings. In that case, you could skip the manual implementation of my_atoi, and just do:

#include <stdlib.h>

void main()
{
    char Operand[2][5] = {{'1', '2', '3', '4', '\0'},{'5', '6', '7', '8', '\0'}};
    signed int Operand1 = atoi(Operand[0]);
    signed int Operand2 = -atoi(Operand[1]);
    signed int Result = Operand1 + Operand2;
}