c_ch01_ex24.c

/*Exercise 1-24. Write a program to check a C program for rudimentary syntax errors like unmatched parentheses, brackets and *braces. Don't forget about quotes, both single and double, escape sequences, and comments. (This program is hard if you do it in full generality.)*/
#include <stdio.h>
#define MAX     1000
char str[MAX];
int rud(int len);
int main()
{
        int ret;
        ret = rud(MAX);
        return 0;
}
int rud(int len) {
        int c, i, lc;
        int parentheses, braces, brackets, quotes, dquotes, parentheses_line, brace_line, bracket_line;
        i = lc = parentheses = braces = brackets = quotes = dquotes = brace_line = bracket_line = parentheses_line = 0;
        while ((c = getchar()) != EOF && i < len - 1 ) {
                if (c == '\n') {
                        lc++;
                        if ((quotes % 2) != 0)
                                printf ("line %d has unclosed quotes\n", lc);
                        if ((dquotes % 2) != 0)
                                printf ("line %d has unclosed double quotes\n", lc);
                        if (!parentheses)
                                parentheses_line = 0;
                        if (!braces)
                                brace_line = 0;
                        if (!brackets)
                                bracket_line = 0;
                        quotes = dquotes = 0;
                }
                if (c == '\'')
                        quotes++;
                if (c == '"')
                        dquotes++;
                if (c == '(') {
                        braces++;
                        brace_line = lc;
                        brace_line++;
                }
                if (c == '[') {
                        brackets++;
                        bracket_line = lc;
                        bracket_line++;
                }
                if (c == '{') {
                        parentheses++;
                        parentheses_line = lc;
                }
                if (c == ')')
                        braces--;
                if (c == ']')
                        brackets--;
                if (c == '}')
                        parentheses--;
                str[i++] = c;
        }
        if (parentheses)
                printf ("line %d has unclosed parentheses\n", parentheses_line);
        if (braces)
                printf ("line %d has unclosed braces\n", brace_line);
        if (brackets)
                printf ("line %d has unclosed brackets\n", bracket_line);
        return 0;
}