io - How to write an array to file in C -

i have 2 dimensional matrix:

char clientdata[12][128]; 

what best way write contents file? need update text file on every write previous data in file cleared.

since size of data fixed, 1 simple way of writing entire array file using binary writing mode:

file *f = fopen("client.data", "wb"); fwrite(clientdata, sizeof(char), sizeof(clientdata), f); fclose(f); 

this writes out whole 2d array @ once, writing on content of file has been there previously.