Thread: strcmp <string.h>

I don't know why program is crashing and on build message i have
"warning: passing arg 1 of 'strcmp' makes pointer from integer without a cast"

I want to compare first character of every string to "_" and if it is "_" exit the loop

Here is my code:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    int i,j;
    char a[20][4];
    char *pa[20];
    for (i=0; i<20; i++)
    {
        pa[i]=&a[i][0];
    }
    for (i=0; i<20; i++)
    {
        scanf("%s",&a[i][0]);
       if (strcmp(*(pa[i]+0),"_")==0)
        {
            printf("ok");
        }
    }
    for (i=0; i<20; i++)
    {
        for (j=0; j<4; j++)
        {
            printf("%c",*(pa[i]+j));
        }
    }
    return 0;
}