C 程序设计语言第二版 第一章 习题

第一题

 

#include <stdio.h>

int main(void){
    printf("hello, world");
    
    return 0;
}

 

第二题

#include <stdio.h>

int main(void){
    printf("hello, world\c12");
    
    return 0;
}

会出现警告，并把c打印出来

 

第三题

#include <stdio.h>

int main(void){
    
    float fahr, celsius;
    int lower, upper, step;
    lower = 0;
    upper = 300;
    step = 20;
    
    fahr = lower;
    printf("Fahrenheit Celsius\n");
    
    while (fahr <= upper) {
        celsius = (5.0 / 9.0) * (fahr - 32.0);
        printf("%6.0f     %6.1f\n", fahr, celsius);
        fahr = fahr + step;
    }
    
    return 0;
}

 

第四题

#include <stdio.h>

int main(void){
    
    float fahr, celsius;
    int lower, upper, step;
    lower = 0;
    upper = 300;
    step = 20;
    
    celsius = lower;
    printf("Celsius Fahrenheit\n");
    
    while (celsius <= upper) {
        fahr = (9.0 / 5.0) * celsius + 32.0;
        printf("%6.0f     %6.1f\n", celsius, fahr);
        celsius = celsius + step;
    }
    
    return 0;
}

 

第五题

#include <stdio.h>

int main(void){
    
    float fahr, celsius;
    int lower, upper, step;
    lower = 0;
    upper = 300;
    step = 20;
    
    
    printf("Fahrenheit Celsius\n");
    
    for (fahr = upper; fahr >=0; fahr = fahr - step) {
        celsius = (5.0 / 9.0) * (fahr - 32.0);
        printf("%6.0f     %6.1f\n", fahr, celsius);
    }
        
    return 0;
}
    

 

第六题

未输入结束符为0，输入结束符为1

 

第七题

#include <stdio.h>

int main(void){
    
    int ch;
    
    while (1) {
        if ((ch = getchar()) == EOF){
            printf("c = %d\n", ch);
            printf("EOF = %d\n", EOF);
            break;
        }
    }
        
    return 0;
}
    

-1

 

第八题

#include <stdio.h>

int main(void){
    
    int space, tab, enter, ch;
    space = tab = enter = 0;
    while ((ch = getchar()) != EOF) {
        if (ch ==  ' ') {
            space++;
        }else if (ch == '\t'){
            tab++;
        }else if (ch == '\n'){
            enter++;
        }
    }
    printf("%d %d %d", space, tab, enter);
    
    return 0;
}
    

 

第9题

#include <stdio.h>

int main(void){
    
    int is_space, ch;
    is_space = 0;
    while ((ch = getchar()) != EOF) {
        if (is_space == 0) {
            if (ch == ' ') {
                putchar(ch);
                is_space = 1;
            }else
                putchar(ch);
        }else{
            if (ch != ' ') {
                putchar(ch);
                is_space = 0;
            }
        }
        
    }
    
    return 0;
}
    

书中的答案更加精简，定义了前一个字符，判断前一个字符的内容实现

 

第十题

#include <stdio.h>

int main(void){
    
    int ch;
    while ((ch = getchar()) != EOF) {
        if (ch == '\t') {
            putchar('\\');
            putchar('t');
        }else if (ch == '\b'){
            putchar('\\');
            putchar('b');
        }else if (ch == '\\'){
            putchar('\\');
            putchar('\\');
        }else
            putchar(ch);
        
    }
    
    return 0;
}
    

 

第十一题

边界测试

 

第十二题

#include <stdio.h>

int main(void){
    
    int ch, last;
    last = '\n';
    while ((ch = getchar()) != EOF) {
        if ((ch == '\t' || ch == ' ' || ch == '\n') && last != '\n') {
            putchar('\n');
            last = '\n';
        }else if (ch == '\t' || ch == ' ' || ch == '\n');
        else{
            putchar(ch);
            last = ch;
        }
        
    }
    
    return 0;
}