prog.c: In function ‘main’:
prog.c:5:2: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘printf’
printf("hello world");
^~~~~~
prog.c:6:2: error: ‘diff’ undeclared (first use in this function)
diff=20-10
^~~~
prog.c:6:2: note: each undeclared identifier is reported only once for each function it appears in
prog.c:7:2: error: expected ‘;’ before ‘printf’
printf("20-10=%f",diff);
^~~~~~
prog.c:4:8: warning: unused variable ‘sum’ [-Wunused-variable]
float sum,diff
^~~