#include <stdio.h> #include <stdlib.h> // 函数声明 int sum_num(int num1, int num2); int main() { int j; j = sum_num(33, 44); printf("j=%d\n", j); //printf("Hello world!\n"); return 0; } // 加法 int sum_num(int num1, int num2) { int result = 0; result = num1 + num2; return result; }