Here is a sample code to write a 2D array of double to a file and read it back. Things work similarly for higher dimensions and dynamically assigned arrays. #include #include int main() { FILE * opfile, * readfile; double var[5][5], varr[5][5]; int i,j,k; for(i = 0; i < 5; i++) for(j = 0; j < 5; j++) var[i][j] = i+j+1; opfile = fopen("storefile", "w"); if(opfile == NULL){ printf("Oops!\n"); return 0; } fwrite(var, sizeof(double), 25, opfile); fclose(opfile); readfile = fopen("storefile", "r"); fread(varr, sizeof(double), 25, opfile); for(i = 0; i < 5; i++){ for(j = 0; j < 5; j ++) printf("%f %f\n", varr[i][j], var[i][j]); } return 0; }