Compilare: main.c: In function 'main': main.c:9:21: warning: operation on 'a' may be undefined [-Wsequence-point] while(b) b ^= a ^= b ^= a %= b; ^~ main.c:9:16: warning: operation on 'b' may be undefined [-Wsequence-point] while(b) b ^= a ^= b ^= a %= b; ^~ main.c:7:15: warning: unused variable 'c' [-Wunused-variable] int a, b, c; ^ main.c:8:5: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d%d",&a,&b); ^~~~~~~~~~~~~~~~~~~~~~~