部分代码如下（编译器为vc＋＋6.0）
char *string1,*string2;
    char *p,*q;
    int locat[10];
    int j,len2,i=0,posit=0;
    printf("Please input string1:\n");
    gets(string1);
    printf("Please input string2:\n");
    gets(string2);
    q=string2;
    for(j=0;*q!='\0';j++,q++)
        len2=j+1;
    p=string1;
    q=string2;
compile时提示
warning C4700: local variable 'string1' used without having been initialized
warning C4700: local variable 'string2' used without having been initialized
调试是出错，请问这是why？