TCPL 习题集 第一章

1-22.c

//超过 80 个字符自动折行。
//折行位置为最近的一个空格，如果没有空格，则从连续文本中断开，加上连字符。

#define MAXLENGTH 80

void newline();
void printArray(char arr[], int pos);

int main(char args[]) {
    newline();
}

void newline() {
    char line[MAXLENGTH];
    int i = 0;
    char c;
    int pos = -1;
    while((c = getchar()) != EOF) {
        if(i == MAXLENGTH) {  //break point!
            if(pos != -1) {
                printArray(line, pos + 1);
                printf("\n");
                i = i - pos;
                for(int j = 0; j < i; ++j) {
                    line[j] = line[pos++];
                }
                pos = -1;
            } else {
                printArray(line, MAXLENGTH - 1);
                printf("-\n");
                i = 1;
                line[0] = line[MAXLENGTH - 1];
            }
        }
        if(c == '\n') {
            printArray(line, i);
            printf("\n");
            i = 0;
            pos = -1;
        } else {
            if(c == ' ') {
                pos = i;
            }
            line[i] = c;
            ++i;
        }
    }
    printArray(line, i);
}

void printArray(char arr[], int pos) {
    for(int i = 0; i < pos; ++i) {
        printf("%c", arr[i]);
    }
}

1-23.c

//忽略注释

#define COMMENT_FIX '/'
#define MULTI_COMMENT '*'

void removeComment();

int main(char args[]) {
    removeComment();
}

void removeComment() {
    char c;
    int begin = 0;
    int inComment = 0;
    int inMultiComment = 0;
    int nearEnd = 0;

    while((c = getchar()) != EOF) {
        if(inComment == 1 && c != '\n') continue;
        if(inMultiComment == 1 && c != MULTI_COMMENT && c != COMMENT_FIX) {
            nearEnd = 0;
            continue;
        }

        if(c == COMMENT_FIX) {
            if(begin == 1 && inMultiComment != 1) {
                inComment = 1;
            } else {
                if(nearEnd == 1) {
                    inMultiComment = 0;
                } else {
                    if(inMultiComment != 1) {
                        begin = 1;
                    }
                }
            }
        } else if(c == MULTI_COMMENT) {
            if(inMultiComment == 1) {
                nearEnd = 1;
            } else if(begin == 1) {
                inMultiComment = 1;
                begin = 0;
                nearEnd = 0;
            } else {
                printf("*");
            }
        } else {
            if(begin == 1 && inComment != 1 && inMultiComment != 1) {
                printf("/");
            }
            printf("%c", c);
            begin = inComment = nearEnd = 0;
        }
    }
}

1-24.c

//检查 C 源码中的括号是否匹配。

#include <stdio.h>
#include <string.h>

#define MAXLEVEL 20

char c;
char bracketStack[MAXLEVEL + 1][3];
int currentLevel = -1;
int lineNum;
int columnNum, lastBracketColumn;
int inError = 0;
int inString, inCharacter, inComment, inMultiComment, begin, nearEnd, inEscape;
int lp, rp, ls, rs, lc, rc; //parenthesis - 圆括号； square bracket - 方括号；curly bracket | brace - 花括号

void testLeftBracket();
void testRightBracket();
char tansformBracket(char); //将括号转成对应部分的括号
void showError(char);

int main() {
    lineNum = columnNum = 1;
    inString = inCharacter = inComment = inMultiComment = begin = nearEnd = inEscape = 0;
    lp = rp = ls = rs = lc = rc = 0;

    while((c = getchar()) != EOF && !inError) {
        columnNum++;
        if(inComment && c != '\n') continue;
        if(inMultiComment && c != '*' && c != '/') {
            if(c == '\n') {
                ++lineNum;
                columnNum = 0;
                printf("\n");
            } else {
                printf(" ");
            }
            nearEnd = 0;
            continue;
        }

        switch(c) {
            case '(':
            case '[':
            case '{':
                if(inString || inCharacter) continue;
                testLeftBracket();
                break;
            case ')':
            case ']':
            case '}':
                if(inString || inCharacter) continue;
                testRightBracket();
                break;
            case '\'':
                if(!inString) {
                    inCharacter = inCharacter ? 0 : 1;
                }
                break;
            case '"':
                if(inString) {
                    if(!inEscape) {
                        inString = 0;
                    }
                } else {
                    if(!inEscape) {
                        inString = 1;
                    }
                }
                break;
            case '/':
                if(begin) {
                    begin = 0;
                    inComment = 1;
                } else if(inMultiComment && nearEnd) {
                    inMultiComment = nearEnd = 0;
                } else {
                    begin = 1;
                }
                continue;
                break;
            case '*':
                if(begin) {
                    begin = 0;
                    inMultiComment = 1;
                } else if(inMultiComment) {
                    nearEnd = 1;
                } else {
                    printf("%c", c);
                }
                continue;
                break;
            case '\\':
                break;
            case '\n':
                ++lineNum;
                columnNum = 0;
                inComment = 0;
                printf("\n");
                continue;
                break;
            default:
                if(begin) {
                    begin = 0;
                }
                break;
        }
        printf("%c", c);
    }

    if(!inError) {
        if(currentLevel >= 0) {
            showError(tansformBracket(bracketStack[currentLevel][0]));
        } else {
            printf("\n\n===========SUCCESS==========\n");
            printf("There's NO ERROR! HOORAY!");
            printf("\n===========SUCCESS END==========");
        }
    }
}

char tansformBracket(char bracket) {
    char result;
    switch (bracket) {
    case '{':
    case '[':
        result = bracket + 2;
        break;
    case '(':
        result = bracket + 1;
        break;
    case ')':
        result = bracket - 1; 
        break;
    case ']':
    case '}':
        result = bracket - 2;
        break;
    default:
        result = ' ';
    }
    return result;
}

void testLeftBracket() {
    ++lp;
    ++currentLevel;
    if(currentLevel >= MAXLEVEL) {
        inError = 1;
        printf("\n The nest is in the MAXIMUM level!");
    }
    bracketStack[currentLevel][0] = c;
    bracketStack[currentLevel][1] = lineNum;
    bracketStack[currentLevel][2] = columnNum;

    bracketStack[currentLevel + 1][0] = '\0';
    lastBracketColumn = columnNum;
}

void testRightBracket() {
    char needBracket = ' ';
    
    if(currentLevel == -1) {
        bracketStack[currentLevel][0] = c;
        bracketStack[currentLevel][1] = lineNum;
        bracketStack[currentLevel][2] = columnNum;
        return showError(tansformBracket(c));
    }
    needBracket = tansformBracket(bracketStack[currentLevel][0]);
    
    if(needBracket != c) {
        bracketStack[currentLevel][0] = c;
        bracketStack[currentLevel][1] = lineNum;
        bracketStack[currentLevel][2] = columnNum;

        showError(needBracket);
    } else {
        bracketStack[currentLevel][0] = '\0';
        --currentLevel;
        if(currentLevel < -1) {
            showError(tansformBracket(c));
        }
    }
}

void showError(char bracket) {
    inError = 1;
    
    printf("\n============ERROR============\n");
    printf("Require '%c'. ERROR is appeared at LINE %d, Column %d", bracket, bracketStack[currentLevel][1], bracketStack[currentLevel][2]);
    printf("\n============ERROR END============\n");
}