hi

use bit wise operators
  & and <<

// note declare the integer d as 32bit long integer.

d = 0;
int swap_a[4][32];


for(int i=0;i,4;i++)
{
d =0;
for(int j=0;j<32;j++)
{
 d = d << 1; // shift bits left 1 position
 d = d | swap_a[i][j];
}
fprintf(dude, "%d", d);
}

// note the resulting the file will contain only the 4 integers