#include <stdio.h>
 
void cat_data(int *data1,const int *data2,int len2){
    for(int i=0;i<len2;i++){
        data1[2+i]=data2[i];   // data1 には最初 2 個入っている
    }
}
 
int main(void) {
    int data1[7]={1,};            
    int data2[5]={3,4,5,6,7};   
 
    int len2=sizeof(data2)/sizeof(data2[0]);
 
    cat_data(data1,data2,len2);
 
    for(int i=0;i<2+len2;i++){
        printf("%d ", data1[i]);
    }
    printf("\n");
 
    return 0;
}
 

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