Compilare: user.c:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int] main(){int a,b;fscanf(fopen("adunare.in","r"),"%d%d",&a,&b);fprintf(fopen("adunare.out","w"),"%d",a+b);} ^ user.c: In function ‘main’: user.c:1:16: warning: implicit declaration of function ‘fscanf’ [-Wimplicit-function-declaration] main(){int a,b;fscanf(fopen("adunare.in","r"),"%d%d",&a,&b);fprintf(fopen("adunare.out","w"),"%d",a+b);} ^ user.c:1:16: warning: incompatible implicit declaration of built-in function ‘fscanf’ user.c:1:16: note: include ‘<stdio.h>’ or provide a declaration of ‘fscanf’ user.c:1:23: warning: implicit declaration of function ‘fopen’ [-Wimplicit-function-declaration] main(){int a,b;fscanf(fopen("adunare.in","r"),"%d%d",&a,&b);fprintf(fopen("adunare.out","w"),"%d",a+b);} ^ user.c:1:23: warning: passing argument 1 of ‘fscanf’ makes pointer from integer without a cast [-Wint-conversion] user.c:1:23: note: expected ‘void *’ but argument is of type ‘int’ user.c:1:61: warning: implicit declaration of function ‘fprintf’ [-Wimplicit-function-declaration] main(){int a,b;fscanf(fopen("adunare.in","r"),"%d%d",&a,&b);fprintf(fopen("adunare.out","w"),"%d",a+b);} ^ user.c:1:61: warning: incompatible implicit declaration of built-in function ‘fprintf’ user.c:1:61: note: include ‘<stdio.h>’ or provide a declaration of ‘fprintf’ user.c:1:69: warning: passing argument 1 of ‘fprintf’ makes pointer from integer without a cast [-Wint-conversion] main(){int a,b;fscanf(fopen("adunare.in","r"),"%d%d",&a,&b);fprintf(fopen("adunare.out","w"),"%d",a+b);} ^ user.c:1:69: note: expected ‘void *’ but argument is of type ‘int’