Atoi Implementation in C

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
char lStr[]="-1234";
int lNum = 0 , i = 0 ;
int lMinus = 1;
if(lStr[0] == '-')
{
lMinus=-1;
}
printf("String Before Conversion [%s]\n",lStr);
for (i=0 ;lStr[i] != '\0';i++)
{
if(lStr[i] == '-')
{
continue;
}
else
lNum=lNum * 10 + lStr[i] - 48;
}
lNum=lNum*lMinus;
printf("String After Conversion [%d]\n",lNum);

return 0;

}