c code for pattern

#include <stdio.h>

#include <string.h>

#include <math.h>

#include <stdlib.h>

int main() {

char str[100];

    int i,j,len,spc,k;

    scanf("%s",str);

    len=strlen(str);

    spc=len;

    for(i=0,j=len-1;i<(len/2)&&j>(len/2);i++,j--){

        spc=spc-2;

        printf("%c",str[i]);

       for(k=1;k<=spc;k++)

            printf(" ");

        printf("%c\n",str[j]);

    }

   j++;

    i--;

    printf("%c\n",str[len/2]);

    for(;i>=0&&j<=len-1;i--,j++){

        printf("%c",str[i]);

        for(k=1;k<=spc;k++)

            printf(" ");

        printf("%c\n",str[j]);

        spc=spc+2;

    }

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   

    return 0;

}