字符串练习题一

青旅半醒 2022-09-20 15:15 183阅读 0赞

/*
    定义char str[2][20]，从键盘输入两个字符
    串保存在此数组中，求这两个字符串中的最大字符
    */
    
    #include <stdio.h>
    #include <string.h>
    
    int main(void)
    {
    	char str[2][20];
    	int i, j;
    	char max_c;
    
    	for(i = 0; i < 2; i++){
    		scanf("%s", str[i]); // str[i]  ==   char(*)[20]
    	}
    	for(i = 0; i < 2; i++){
    		printf("%s ", str[i]);
    	}
    	printf("\n");
    	
    	max_c = str[0][0];
    	for(i = 0; i < 2; i++){
    		for(j = 0; str[i][j] != '\0'; j++){
    			if(str[i][j] > max_c ) {
    					max_c = str[i][j];
    			}
    		}
    	}
    
    
    	printf("%c\n", max_c);
    
    	return 0;
    }
    
    /*
    dawxd adaz
    dawxd adaz 
    z
    */<pre name="code" class="cpp">
    
    
    /*
    自己编写程序实现void itoa(int x, char *str)(将数字x，
    转换为字符串并保存到str中,即如：54639 转成‚54639‛)
    */
    #include <stdio.h>
    #include <string.h>
    
    void itoa(int x, char *str)
    {
    //	char str[20];
    	int i=0, j;
    	char str_l[20];
    	do{
    		str[i] = x%10 + '0';
    		i++;
    	
    	}while( (x = x/10) != 0 );
    
    	str[i] = '\0';
    	str_l[i] = str[i];
    
    	for(--i, j = 0; i >= 0 ; i--, j++ ){
    				str_l[j] = str[i];
    	}
    
    	strcpy(str, str_l); 
    	printf("%s\n", str);
    }
    
    int main(void)
    {
    	int n;
    	char str[20];
    	scanf("%d", &n);
    	itoa(n, str);
    
    	return 0;
    }
    
    /*
    akaedu@akaedu-G41MT-D3:~/lin/721_string$ ./2
    785511
    785511
    */<pre name="code" class="cpp">
    
    /*
    统计子串substr在源串src中出现的次数。
    源串及子串数据从命令行参数获取。
    */
    
    #include <stdio.h>
    #include <string.h>
    
    int main(int argc, char **argv)
    {
    	char *retp, *begin;
    	int count = 0;
    	int substrlen = 0;
    	retp = strstr(argv[1], argv[2]);
        
    	if(argc != 3){
    		printf("Usage:./a.out substr src\n");
    		return 0;
    	}
    
    
    	if(argv[2][0] == '\0'){
    		printf("count = 0\n");
    		return 0;
    	}
    
    
    	for(begin = argv[1], substrlen = strlen(argv[2]); (retp = strstr(begin, argv[2]));
    														begin = retp + substrlen ){
    														
    			count++;												
    		}
    
    
    	printf("count:%d\n", count);
    
    
    	return 0;
    
    }
    
    /*
    akaedu@akaedu-G41MT-D3:~/lin/721_string$ ./4 adadadad ''
    count = 0
    akaedu@akaedu-G41MT-D3:~/lin/721_string$ ./4 adadadad '' a
    Usage:./a.out substr src
    akaedu@akaedu-G41MT-D3:~/lin/721_string$ ./4 adadadad ad
    count:4
    
    
    */<pre name="code" class="cpp">
    
    
    /*
    若有字符串http://www.google.cn/search?complete=1&hl=zh-CN&ie=GB2312&q=linux&meta=
    用于进行数据搜索，使用库函数分别解析出key与value数据。程序运行后显示：
    key = complete value = 1
    key = hl value = zh-CN
    …
    */
    
    #include <stdio.h>
    #include <string.h>
    
    int main(void)
    {
    	char str[] = "http://www.google.cn/search?complete=1&hl=zh-CN&ie=GB2312&q=linux&meta=";
    	char *value, *begin, *key;
    	puts(str);
    
    	begin = strchr(str, '?') + 1;
    
    	for(; (key = strtok(begin, "&")); begin = NULL ){
    		key = strtok_r(key, "=", &value);
    		if( !key ){        //(key == 0)
    			break;
    		}
    		printf("key:%s value:%s\n", key, value);
    	}
    
    
    	return 0;
    }
    
    /*
    akaedu@akaedu-G41MT-D3:~/lin/722_str$ ./2
    http://www.google.cn/search?complete=1&hl=zh-CN&ie=GB2312&q=linux&meta=
    key:complete value:1
    key:hl value:zh-CN
    key:ie value:GB2312
    key:q value:linux
    key:meta value:
    */