File I/O

int main() {
    ofstream out("out.out");
    for (int i = 0; i < 10; i++) {
        out << i << " " << i * 2 << endl;
    }
    out.close();
    cout << "done1" << endl;
    ifstream openFile("out.out");
    int T;
    //openFile >> T;
    long long tmp,k;
    while (openFile && !openFile.eof()) {
        openFile >> tmp >> k;
        if (openFile.eof()) {
            break;
        }
        printf("%lld %lld\n", tmp,k);
    } ;
    openFile.close();
    cout << "done2" << endl;
    while(1){}
    return 0;
}

C style

#include <stdio.h>
 
int main(){
 
        FILE *fp ;
 
        int index;
 
        int data;
 
 
 
        fp = fopen("test.txt", "w");
 
        for(index = 0 ; index < 10 ; index++){
 
                fprintf(fp, "%d\n", index);
 
        }
 
 
 
        fclose(fp);
 
 
 
        fp = fopen("test.txt", "r");
 
 
 
        while(fscanf(fp, "%d", &data) != EOF){
 
                printf("%d\n", data);
 
 
 
        }
 
 
 
        fclose(fp);
 
        return 0;
 
}
 
 
 
출처: http://ra2kstar.tistory.com/53 [초보개발자 이야기.]