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brainfuck.c
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brainfuck.c
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void putchar(char c);
void *malloc(int size);
int getchar();
int printf(char *s, ...);
int main() {
int size = 10000;
int *cell = malloc(10000 * 4);
for (int i = 0; i < size; i++) {
cell[i] = 0;
}
char *program = malloc(10000);
for (int i = 0;; i++) {
char c = getchar();
//printf("program=%x, c=%c, i=%d\n", program, c, i);
program[i] = c;
if (c == '!') {
program[i] = 0;
break;
}
}
int pc = 0;
int ptr = 0;
while (1) {
char c = program[pc];
//printf("pc=%d, %c\n", pc, c);
if (!c) {
printf("end\n");
break;
}
if (c == '+') {
program[ptr]++;
pc++;
} else if (c == '-') {
program[ptr]--;
pc++;
} else if (c == '<') {
ptr--;
if (ptr < 0) {
ptr += size;
}
pc++;
} else if (c == '>') {
ptr++;
if (ptr >= size) {
ptr -= size;
}
pc++;
} else if (c == ',') {
program[ptr] = getchar();
pc++;
} else if (c == '.') {
putchar(program[ptr]);
pc++;
} else if (c == '[') {
if (program[ptr]) {
pc++;
} else {
int cnt = 0;
while (1) {
c = program[pc];
if (c == '[') {
cnt++;
}
if (c == ']') {
cnt--;
if (cnt == 0)
break;
}
pc++;
}
pc++;
}
} else if (c == ']') {
if (!program[ptr]) {
pc++;
} else {
int cnt = 0;
while (1) {
c = program[pc];
if (c == ']') {
cnt++;
}
if (c == '[') {
cnt--;
if (cnt == 0)
break;
}
pc--;
}
pc++;
}
} else {
pc++;
}
}
}