求和为某数的两个数字组合

给定排好序的数字，求和为某数的两个数字组合。

#include <stdio.h>

struct Pair{
    int f;
    int s;
} ;

int find(int num[], int n, int x, struct Pair pairs[]){
    int i = 0;
    int j = n - 1;
    int m = 0;
    for(; i < j; ){
        if(num[i] + num[j] < x) i++;
        else if(num[i] + num[j] > x) j--;
        else{
            pairs[m].f = num[i];
            pairs[m].s = num[j];
            i++;
            j--;
            m++;
        }
    }
    return m;
}


main(){
    int i;
    struct Pair pairs[10];
    int num[] = {1, 2, 3, 4, 5, 6, 7, 8};
    int n = 8;
    int x = 9;
    int m;
    m = find(num, n, x, pairs);

    for(i = 0; i < m; i++)
        printf("%d %d\n", pairs[i].f, pairs[i].s);
}