Return multiple levels up in the call stack

0_return-multi-level.cc

#if false
g++ $0 && ./a.out
exit
#endif

// Modified code that demonstrates a code with multi-level return

#include <stdio.h>

void print_enter(const char* function_name) {
    printf("Entering %s\n", function_name);
}

void print_exit(const char* function_name) {
    printf("Exiting %s\n", function_name);
}

int level_10() {
    print_enter("level_10");
    print_exit("level_10");
    return 0;
}

int level_9() {
    print_enter("level_9");
    // return 3 levels up in the call stack
    return 2;
    int l = level_10();
    if (l) return l-1;
    print_exit("level_9");
    return 0;
}

int level_8() {
    print_enter("level_8");
    int l = level_9();
    if (l) return l-1;
    print_exit("level_8");
    return 0;
}

int level_7() {
    print_enter("level_7");
    int l = level_8();
    if (l) return l-1;
    print_exit("level_7");
    return 0;
}

int level_6() {
    print_enter("level_6");
    int l = level_7();
    if (l) return l-1;
    print_exit("level_6");
    return 0;
}

int level_5() {
    print_enter("level_5");
    int l = level_6();
    if (l) return l-1;
    print_exit("level_5");
    return 0;
}

int level_4() {
    print_enter("level_4");
    int l = level_5();
    if (l) return l-1;
    print_exit("level_4");
    return 0;
}

int level_3() {
    print_enter("level_3");
    int l = level_4();
    if (l) return l-1;
    print_exit("level_3");
    return 0;
}

int level_2() {
    print_enter("level_2");
    int l = level_3();
    if (l) return l-1;
    print_exit("level_2");
    return 0;
}

int level_1() {
    print_enter("level_1");
    int l = level_2();
    if (l) return l-1;
    print_exit("level_1");
    return 0;
}

int main() {
    print_enter("main");
    level_1();
    print_exit("main");
    return 0;
}

1_return-multi-level-template.cc

#if false
g++ $0 && ./a.out
exit
#endif

// Modified code with transformation to the code with multi-level return capability

#include <stdio.h>

void print_enter(const char* function_name) {
    printf("Entering %s\n", function_name);
}

void print_exit(const char* function_name) {
    printf("Exiting %s\n", function_name);
}

int level_10() {
    print_enter("level_10");
    print_exit("level_10");
    return 0;
}

int level_9() {
    print_enter("level_9");
    int l = level_10();
    if (l) return l-1;
    print_exit("level_9");
    return 0;
}

int level_8() {
    print_enter("level_8");
    int l = level_9();
    if (l) return l-1;
    print_exit("level_8");
    return 0;
}

int level_7() {
    print_enter("level_7");
    int l = level_8();
    if (l) return l-1;
    print_exit("level_7");
    return 0;
}

int level_6() {
    print_enter("level_6");
    int l = level_7();
    if (l) return l-1;
    print_exit("level_6");
    return 0;
}

int level_5() {
    print_enter("level_5");
    int l = level_6();
    if (l) return l-1;
    print_exit("level_5");
    return 0;
}

int level_4() {
    print_enter("level_4");
    int l = level_5();
    if (l) return l-1;
    print_exit("level_4");
    return 0;
}

int level_3() {
    print_enter("level_3");
    int l = level_4();
    if (l) return l-1;
    print_exit("level_3");
    return 0;
}

int level_2() {
    print_enter("level_2");
    int l = level_3();
    if (l) return l-1;
    print_exit("level_2");
    return 0;
}

int level_1() {
    print_enter("level_1");
    int l = level_2();
    if (l) return l-1;
    print_exit("level_1");
    return 0;
}

int main() {
    print_enter("main");
    level_1();
    print_exit("main");
    return 0;
}

2_return-multi-level-original.cc

#if false
g++ $0 && ./a.out
exit
#endif

// Original code without transformation to the code with multi-level return capability

#include <stdio.h>

void print_enter(const char* function_name) {
    printf("Entering %s\n", function_name);
}

void print_exit(const char* function_name) {
    printf("Exiting %s\n", function_name);
}

void level_10() {
    print_enter("level_10");
    print_exit("level_10");
}

void level_9() {
    print_enter("level_9");
    level_10();
    print_exit("level_9");
}

void level_8() {
    print_enter("level_8");
    level_9();
    print_exit("level_8");
}

void level_7() {
    print_enter("level_7");
    level_8();
    print_exit("level_7");
}

void level_6() {
    print_enter("level_6");
    level_7();
    print_exit("level_6");
}

void level_5() {
    print_enter("level_5");
    level_6();
    print_exit("level_5");
}

void level_4() {
    print_enter("level_4");
    level_5();
    print_exit("level_4");
}

void level_3() {
    print_enter("level_3");
    level_4();
    print_exit("level_3");
}

void level_2() {
    print_enter("level_2");
    level_3();
    print_exit("level_2");
}

void level_1() {
    print_enter("level_1");
    level_2();
    print_exit("level_1");
}

int main() {
    print_enter("main");
    level_1();
    print_exit("main");
    return 0;
}