函数的说明函数在被调用前必须先定义或说明 void main( void swap(int a, int b Intx, y int t void swap(int a, int b); t=a scanf(%od%d",&x, &y) a= b Swap(x b=t printf("od%",x,y) void main void swap(int a, int b) Int x,y; Int t scanf("%od%od",&x, &y) t= a swap(x, y) a=b printf("%od%d",x,y)函数的说明 void swap(int a, int b) { int t; t = a; a = b; b = t; } void main( ) { int x, y; scanf("%d%d", &x, &y); swap(x, y); printf("%d%d", x, y); } void main( ) { int x, y; scanf("%d%d", &x, &y); swap(x, y); printf("%d%d", x, y); } void swap(int a, int b) { int t; t = a; a = b; b = t; } void swap(int a, int b); 函数在被调用前必须先定义或说明！