Compilare: main.c:3:6: warning: return type of 'main' is not 'int' [-Wmain] void main () { ^~~~ main.c: In function 'main': main.c:5:34: warning: variable 'xj' set but not used [-Wunused-but-set-variable] int i,j,mi,mj,min_i,min_j,xi,xj; ^~ main.c:5:31: warning: variable 'xi' set but not used [-Wunused-but-set-variable] int i,j,mi,mj,min_i,min_j,xi,xj; ^~ main.c:12:5: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf (f_in, "%d%d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:20:13: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf (f_in, "%d", &tabla[i][j]); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:42:13: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf (f_in, "%d", &tabla[i][j]); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:78:21: warning: 'min_j' may be used uninitialized in this function [-Wmaybe-uninitialized] s=s+((min_i*(-1)+min_j*(-1))*2); ~~~~~~~~~~~^~~~~~~~~~~~ main.c:78:16: warning: 'min_i' may be used uninitialized in this function [-Wmaybe-uninitialized] s=s+((min_i*(-1)+min_j*(-1))*2); ~~~~~^~~~~