my atoi

#include

int myatoi(char* string)
{
int value = 0;
if(string)
{
while(*string && *string>='0' && *string<='9')
{
value = value*10 + (*string - '0');
string++;
}
}
return value;
}
int main()
{
printf("char value is %d\n","1989");
printf("int value is %10d\n",myatoi("1989"));
return 0;
}