Question

How to create recursive implementation of atoi() for positive and negative numbers in C

Answer 1

#include <stdio.h>

long _atoi(const char *str) {
    long num = 0;
    int i = 0, sign = 1;

    if (str[i] == '+' || str[i] == '-') {
        if (str[i] == '-') {
            sign = -1;
        }
        i++;
    }
 
    while (str[i] && (str[i] >= '0' && str[i] <= '9')) {
        num = num * 10 + (str[i] - '0');
        i++;
    }
 
    return sign * num;
}
  
int main()
{
    char str[] = "-96291807235";
     
    long n = _atoi(str);
     
    printf("%ld", n);
     
    return 0;
}
 
 
 
 
/*
run:
      
-96291807235
 
*/

 

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