/in/ex1.c: In function 'main':
/in/ex1.c:6:5: error: 'complex' undeclared (first use in this function)
     complex  double a = d + e * _Complex_I;
     ^~~~~~~
/in/ex1.c:6:5: note: each undeclared identifier is reported only once for each function it appears in
/in/ex1.c:6:14: error: expected ';' before 'double'
     complex  double a = d + e * _Complex_I;
              ^~~~~~
/in/ex1.c:7:14: error: expected ';' before 'double'
     complex  double b = f + g * _Complex_I;
              ^~~~~~
/in/ex1.c:8:14: error: expected ';' before 'double'
     complex  double c = h + i * _Complex_I;
              ^~~~~~
/in/ex1.c:9:21: error: 'd' undeclared (first use in this function)
     scanf("%f%f\n",&d,&e);
                     ^
/in/ex1.c:9:24: error: 'e' undeclared (first use in this function)
     scanf("%f%f\n",&d,&e);
                        ^
/in/ex1.c:10:21: error: 'f' undeclared (first use in this function)
     scanf("%f%f\n",&f,&g);
                     ^
/in/ex1.c:10:24: error: 'g' undeclared (first use in this function)
     scanf("%f%f\n",&f,&g);
                        ^
/in/ex1.c:11:5: error: 'h' undeclared (first use in this function)
     h=d+f;
     ^
/in/ex1.c:12:5: error: 'i' undeclared (first use in this function)
     i=g+i;
     ^
/in/ex1.c:13:5: error: 'c' undeclared (first use in this function)
     c = h + i * _Complex_I;
     ^
/in/ex1.c:13:17: error: '_Complex_I' undeclared (first use in this function)
     c = h + i * _Complex_I;
                 ^~~~~~~~~~
/in/ex1.c:15:5: error: expected ';' before 'return'
     return 0;
     ^~~~~~