Compilare: user.c:1:1: warning: return type defaults to ‘int’ [enabled by default] main(){int a,b,i=1;long long t=0;fscanf(fopen("ndiv.in","r"),"%d%d",&a,&b);for(;i*i<a;++i)t-=2*((a-1)/i-i)+1;for(i=1;i*i<=b;i++)t+=2*(b/i-i)+1;fprintf(fopen("ndiv.out","w"),"%lld",t);} ^ user.c: In function ‘main’: user.c:1:1: warning: implicit declaration of function ‘fscanf’ [-Wimplicit-function-declaration] user.c:1:34: warning: incompatible implicit declaration of built-in function ‘fscanf’ [enabled by default] main(){int a,b,i=1;long long t=0;fscanf(fopen("ndiv.in","r"),"%d%d",&a,&b);for(;i*i<a;++i)t-=2*((a-1)/i-i)+1;for(i=1;i*i<=b;i++)t+=2*(b/i-i)+1;fprintf(fopen("ndiv.out","w"),"%lld",t);} ^ user.c:1:1: warning: implicit declaration of function ‘fopen’ [-Wimplicit-function-declaration] main(){int a,b,i=1;long long t=0;fscanf(fopen("ndiv.in","r"),"%d%d",&a,&b);for(;i*i<a;++i)t-=2*((a-1)/i-i)+1;for(i=1;i*i<=b;i++)t+=2*(b/i-i)+1;fprintf(fopen("ndiv.out","w"),"%lld",t);} ^ user.c:1:1: warning: passing argument 1 of ‘fscanf’ makes pointer from integer without a cast [enabled by default] user.c:1:1: note: expected ‘void *’ but argument is of type ‘int’ user.c:1:1: warning: implicit declaration of function ‘fprintf’ [-Wimplicit-function-declaration] user.c:1:144: warning: incompatible implicit declaration of built-in function ‘fprintf’ [enabled by default] main(){int a,b,i=1;long long t=0;fscanf(fopen("ndiv.in","r"),"%d%d",&a,&b);for(;i*i<a;++i)t-=2*((a-1)/i-i)+1;for(i=1;i*i<=b;i++)t+=2*(b/i-i)+1;fprintf(fopen("ndiv.out","w"),"%lld",t);} ^ user.c:1:1: warning: passing argument 1 of ‘fprintf’ makes pointer from integer without a cast [enabled by default] main(){int a,b,i=1;long long t=0;fscanf(fopen("ndiv.in","r"),"%d%d",&a,&b);for(;i*i<a;++i)t-=2*((a-1)/i-i)+1;for(i=1;i*i<=b;i++)t+=2*(b/i-i)+1;fprintf(fopen("ndiv.out","w"),"%lld",t);} ^ user.c:1:1: note: expected ‘void *’ but argument is of type ‘int’