Compilare: user.c:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c: In function ‘main’: user.c:1:1: warning: type of ‘a’ defaults to ‘int’ [-Wimplicit-int] user.c:1:1: warning: type of ‘b’ defaults to ‘int’ [-Wimplicit-int] user.c:1:11: warning: implicit declaration of function ‘fscanf’ [-Wimplicit-function-declaration] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:11: warning: incompatible implicit declaration of built-in function ‘fscanf’ user.c:1:11: note: include ‘<stdio.h>’ or provide a declaration of ‘fscanf’ user.c:1:18: warning: implicit declaration of function ‘fopen’ [-Wimplicit-function-declaration] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:18: warning: passing argument 1 of ‘fscanf’ makes pointer from integer without a cast [-Wint-conversion] user.c:1:18: note: expected ‘void *’ but argument is of type ‘int’ user.c:1:66: warning: operation on ‘a’ may be undefined [-Wsequence-point] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:63: warning: operation on ‘b’ may be undefined [-Wsequence-point] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:76: warning: implicit declaration of function ‘fprintf’ [-Wimplicit-function-declaration] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:76: warning: incompatible implicit declaration of built-in function ‘fprintf’ user.c:1:76: note: include ‘<stdio.h>’ or provide a declaration of ‘fprintf’ user.c:1:84: warning: passing argument 1 of ‘fprintf’ makes pointer from integer without a cast [-Wint-conversion] main(a,b){fscanf(fopen("cmmdc.in","r"),"%d%d",&a,&b);while(b)b^=a^=b^=a%=b;fprintf(fopen("cmmdc.out","w"),"%d",a==1?0:a);} ^ user.c:1:84: note: expected ‘void *’ but argument is of type ‘int’