c代码中的错误

我有一个交流代码，它给我的错误是分段错误，这个错误意味着我没有得到它。 这是代码：

#include  #include  #include  #include  #define STREQUAL(a,b) (strcmp(a,b) == 0) /* State of the 54-card deck. This keeps a spare deck for copying into. It also has three spare slots *behind* the start of the deck: two so the deck can be moved backward if a joker is moved from the bottom to the top in the first step, and one so that the reference to the card before the first joker always points somewhere even when there's a joker on the top of the pack. */ typedef struct SolState_t { int a, b; int *deck, *spare; int deck1[57], deck2[57]; } SolState_t ; SolState_t state; int verbose = 0; int lastout, cocount; #define JOKER_STEP(var,ovar) \ (((var != 53) ? \ (source[var] = source[var +1], var++) : \ (source--, ovar++, source[0] = source[1], var = 1)), \ ((var == ovar)?(ovar--):0)) /* Cycle the state for "rounds" outputs, skipping jokers as usual. "lastout" is the last output, which is never a joker. If "rounds" is zero though, cycle the state just once, even if the output card is a joker. "lastout" may or may not be set. This is only useful for key setup. Note that for performance reasons, this updates the coincidence statistics under all circumstances, so they need to be set to zero immediately before the large batch run. */ static void cycle_deck( int rounds ) { int *source, *s, *sb, *d; int lo, hi; int nlo, nhi, nccut; int output; do { assert(state.a != state.b); assert(state.deck[state.a] == 53); assert(state.deck[state.b] == 53); source = state.deck; JOKER_STEP(state.a,state.b); JOKER_STEP(state.b,state.a); JOKER_STEP(state.b,state.a); source[state.a] = 53; source[state.b] = 53; if (state.a < state.b) { lo = state.a; hi = state.b + 1; } else { lo = state.b; hi = state.a + 1; } nlo = 54 - hi; nhi = 54 - lo; /* We do both the triple cut and the count cut as one copying step; this means handling four separate cases. */ nccut = source[lo -1]; s = source; if (lo == 0) { /* There's a joker on the top of the pack. This can only happen in one exact circumstance, but when it does nccount is wrong. So we handle it specially. */ assert(state.a == 0); assert(state.b == 2); d = &state.spare[51]; sb = &source[3]; while(s < sb) {*d++ = *s++;} d = &state.spare[0]; sb = &source[54]; while(s < sb) {*d++ = *s++;} state.a = 51; state.b = 53; } else if (nccut <= nlo) { /* The second cut is before the first joker. */ d = &state.spare[nhi - nccut]; sb = &source[lo -1]; while(s < sb) {*d++ = *s++;} state.spare[53] = *s++; d = &state.spare[nlo - nccut]; sb = &source[hi]; while(s < sb) {*d++ = *s++;} d = &state.spare[53 - nccut]; sb = &source[nccut + hi]; /* ccut */ while(s < sb) {*d++ = *s++;} d = &state.spare[0]; sb = &source[54]; while(s < sb) {*d++ = *s++;} state.a += nlo - nccut - lo; state.b += nlo - nccut - lo; } else if (nccut < nhi) { /* The second cut is between the two jokers */ d = &state.spare[nhi - nccut]; sb = &source[lo -1]; while(s < sb) {*d++ = *s++;} state.spare[53] = *s++; d = &state.spare[53 - nccut + nlo]; sb = &source[nccut - nlo + lo]; /* ccut */ while(s < sb) {*d++ = *s++;} d = &state.spare[0]; sb = &source[hi]; while(s < sb) {*d++ = *s++;} d = &state.spare[53 - nccut]; sb = &source[54]; while(s < sb) {*d++ = *s++;} if (state.a < state.b) { state.a = 53 - nccut + nlo; state.b = nhi - nccut -1; } else { state.b = 53 - nccut + nlo; state.a = nhi - nccut -1; } } else { /* The second cut is after the last joker. */ d = &state.spare[53 - nccut + nhi]; sb = &source[nccut - nhi]; /* ccut */ while(s < sb) {*d++ = *s++;} d = &state.spare[0]; sb = &source[lo -1]; while(s < sb) {*d++ = *s++;} state.spare[53] = *s++; d = &state.spare[53 - nccut + nlo]; sb = &source[hi]; while(s < sb) {*d++ = *s++;} d = &state.spare[53 - nccut]; sb = &source[54]; while(s = 26) { if (output >= 52) { if (output > 52) continue; output = 0; } else { output -= 26; } } cocount += (lastout == output); lastout = output; rounds--; } while (rounds > 0); } static void print_deck( ) { int i; for (i = 0; i < 54; i++) { if (state.deck[i] < 53) { putchar(' ' + state.deck[i]); } else if (i == state.a) { putchar('U'); } else { assert(i == state.b); putchar('V'); } } } /* Key the deck with a passphrase. */ static void key_deck( char *key ) { int i, kval, *tmp; state.deck = state.deck1 + 3; state.spare = state.deck2 + 3; for (i = 0; i = 'A' && *key <= 'Z' ) { cycle_deck(0); /* Special value '0' is only useful here... */ /* And now perform a second count cut based on the key letter */ kval = *key - 'A' + 1; for (i = 0; i  %c\n", char_in, char_out); } return char_out; } int main( int argc, char *argv[] ) { char **av = argv, *tmp; int slow_mode = 0; long rounds; /* Skip the name of the program */ av++; argc--; if (argc  2) { if (STREQUAL(*av, "-v")) { verbose = 1; } else if (STREQUAL(*av, "-s")) { slow_mode = 1; } else { printf ("Unrecognised flag: %s\n", *av); exit(-1); } av++; argc--; } key_deck(av[0]); rounds = strtol(av[1], &tmp, 0); if (*tmp != '\0') { /* It's not a number - so it's a string! */ char *text = av[1]; int i = 0; for (; *text != '\0'; text++) { if (*text >= 'A' && *text  0 && (i % 5) == 0) putchar(' '); putchar(encrypt_char(*text)); i++; } } while ((i % 5) != 0) { putchar(encrypt_char('X')); i++; } putchar('\n'); } else { /* Treat it as a sequence of 'A's. */ int i; if (rounds <= 0) { printf("Rounds number must be greater than zero\n"); exit(-1); } if (verbose || slow_mode) { for (i = 0; i < rounds; i++) encrypt_char('A'); } else { cycle_deck(rounds); } printf("Coincidences: %d / %ld\n", cocount, rounds -1); } return 0; } 

Answer 1

分段故障。

编辑答案以响应您的编辑，尝试使用GDB：运行：gdb myapp.exe然后给出命令“start”，然后在“step”之后直到遇到问题。 它将帮助您将问题区域缩小到一个特定的function。

我应该提到在调试时获取完整信息，使用“-g”开关进行编译（使用gcc）。 有关GDB的完整教程，请点击此处

Answer 2

分段错误表示存储器访问冲突。 它通常是在C语言编程时解除引用悬空指针或访问超出范围的数组索引的结果。

尝试使用gdb逐步执行程序并确定发生分段错误的位置。