#include <stdio.h> #include <stdint.h> int custom_atoi(const char *str) { int val = 0; char first_char; while(*str == ' ' || *str == '\n'){ str++; } //remove leading whitespaces first_char = *str; //assign sign if present if(first_char == '+' || first_char == '-'){ str++; } while( (*str >= '0') && (*str <= '9') ){ val = (val*10) + (*str - '0'); str++; } return (first_char == '-') ? -val : val; //convert to negative } int main() { char str[101]; fgets(str, sizeof(str), stdin); // Remove newline uint8_t i = 0; while (str[i]) { if (str[i] == '\n') { str[i] = '\0'; break; } i++; } printf("%d", custom_atoi(str)); return 0; }
Test Cases
Test Results
Input
123abc
Expected Output
123