Code:I have got some truble,like these: dream@liuguobiao:~/Desktop$ cat c.c #include <stdio.h> #include <string.h> int main() { string st; st = Getline(); return 0; } dream@liuguobiao:~/Desktop$ gcc -o c c.c c.c: In function 'main': c.c:6: error: 'string' undeclared (first use in this function) c.c:6: error: (Each undeclared identifier is reported only once c.c:6: error: for each function it appears in.) c.c:6: error: expected ';' before 'st' c.c:7: error: 'st' undeclared (first use in this function) dream@liuguobiao:~/Desktop$ why it said "string undeclared" ? I can find "string.h" in "/usr/include" but why i can't use 'string' declared the 'st' ? help me ......