Convert String to Integer

Code

#include <stdio.h>
#include <stdint.h>

int custom_atoi(const char *str) {
    int data=0;
    int negative = 0;
    while(*str ){
        
        if((('0'<=*str) & (*str<='9')) || (*str=='-') |(*str=='+') )
            {
                
                if(data==0){
                    if((*str) =='-'){
                        negative = 1;
                        str++;
                        continue;
                    }
                    if((*str) =='+'){
                        str++;
                        continue;
                    }
                    data = *str - '0';
                }
                else{
                    data = (data *10) + (*str-'0');
                    
                }
               
            }
            else{
                break;
            }
            
        str++;
            }
    if(negative==1)
        return 0-data;
    return data;
}

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;
}

Solving Approach

 

 

 

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Input

123abc

Expected Output

123