prog.c:2:1: warning: return type defaults to ‘int’ [-Wreturn-type]
main() {
^
prog.c: In function ‘main’:
prog.c:4:1: error: ‘for’ loop initial declarations are only allowed in C99 mode
for (int i=1; i<=100; i++)
^
prog.c:4:1: note: use option -std=c99 or -std=gnu99 to compile your code
prog.c:6:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^