Longest Common Prefix

Write a function to find the longest common prefix string amongst an array of strings.

#include<stdio.h>#include<string.h>#include<stdlib.h>char *longestCommonPrefix(char *strs[],int n){    int i,j,k;    char *res=(char *)malloc(sizeof(char)*1000);    char *p=strs[0];    char *q=strs[1];    //printf("%s,%c\n",q,q[1]);    //printf("%s\n",p);    if(p==NULL) return "";    if(q==NULL) return p;    for(i=0;p[i]!='\0' && q[i]!='\0';i++){        if(p[i]==q[i]) res[i]=p[i];        else break;    }    res[i]='\0';    for(k=2,q=strs[k];k<n;k++){        for(i=0;res[i]!='\0'&&strs[k][i]!='\0';i++){            if(res[i]!=strs[k][i]) break;        }        res[i]='\0';    }    return res;}void main(){    char *str[]={"abc","a","abcd"};    char *str1[]={"a","b"};    printf("%s\n",longestCommonPrefix(str1,2));}